20506320 has 120 divisors (see below), whose sum is σ = 72540000. Its totient is φ = 5177088.

The previous prime is 20506319. The next prime is 20506327. The reversal of 20506320 is 2360502.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 20506293 and 20506302.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20506327) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12931 + ... + 14429.

It is an arithmetic number, because the mean of its divisors is an integer number (604500).

Almost surely, 2^20506320 is an apocalyptic number.

20506320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20506320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36270000).

20506320 is an abundant number, since it is smaller than the sum of its proper divisors (52033680).

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

20506320 is a wasteful number, since it uses less digits than its factorization.

20506320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1537 (or 1528 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

The square root of 20506320 is about 4528.3904425303. The cubic root of 20506320 is about 273.7133058967.

Adding to 20506320 its reverse (2360502), we get a palindrome (22866822).

The spelling of 20506320 in words is "twenty million, five hundred six thousand, three hundred twenty".