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1520 = 24519

1520 has 20 divisors (see below), whose sum is σ = 3720. Its totient is φ = 576.

The previous prime is 1511. The next prime is 1523. The reversal of 1520 is 251.

1520 = T5 + T6 + ... + T20.

It is a Cunningham number, because it is equal to 392-1.

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (8).

It is a plaindrome in base 13.

It is a zygodrome in base 4.

It is a junction number, because it is equal to n+sod(n) for n = 1498 and 1507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1523) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71 + ... + 89.

It is an arithmetic number, because the mean of its divisors is an integer number (186).

1520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1520 is the 32-nd pentagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1860).

1520 is an abundant number, since it is smaller than the sum of its proper divisors (2200).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1520 is a wasteful number, since it uses less digits than its factorization.

With its successor (1521) it forms a Ruth-Aaron pair, since the sum of their prime factors is the same (32).

1520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32 (or 26 counting only the distinct ones).

The product of its (nonzero) digits is 10, while the sum is 8.

The square root of 1520 is about 38.9871773792. The cubic root of 1520 is about 11.4977941579.

Adding to 1520 its reverse (251), we get a palindrome (1771).

It can be divided in two parts, 15 and 20, that multiplied together give a triangular number (300 = T24).

The spelling of 1520 in words is "one thousand, five hundred twenty".

Divisors: 1 2 4 5 8 10 16 19 20 38 40 76 80 95 152 190 304 380 760 1520