20551320 has 80 divisors (see below), whose sum is σ = 69086160. Its totient is φ = 5479488.

The previous prime is 20551303. The next prime is 20551367. The reversal of 20551320 is 2315502.

It is a happy number.

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 = 20551293 and 20551302.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 69 + ... + 6411.

It is an arithmetic number, because the mean of its divisors is an integer number (863577).

Almost surely, 2^20551320 is an apocalyptic number.

20551320 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 20551320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34543080).

20551320 is an abundant number, since it is smaller than the sum of its proper divisors (48534840).

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

20551320 is a wasteful number, since it uses less digits than its factorization.

20551320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6366 (or 6353 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 20551320 is about 4533.3563724905. The cubic root of 20551320 is about 273.9133759239.

Adding to 20551320 its reverse (2315502), we get a palindrome (22866822).

It can be divided in two parts, 2055 and 1320, that added together give a cube (3375 = 15³).

The spelling of 20551320 in words is "twenty million, five hundred fifty-one thousand, three hundred twenty".