20515304056 has 64 divisors (see below), whose sum is σ = 42140851200. Its totient is φ = 9305670528.

The previous prime is 20515304041. The next prime is 20515304071. The reversal of 20515304056 is 65040351502.

It is an interprime number because it is at equal distance from previous prime (20515304041) and next prime (20515304071).

It is a super-2 number, since 2×20515304056² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3223005 + ... + 3229363.

It is an arithmetic number, because the mean of its divisors is an integer number (658450800).

Almost surely, 2^20515304056 is an apocalyptic number.

20515304056 is a gapful number since it is divisible by the number (26) 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 20515304056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21070425600).

20515304056 is an abundant number, since it is smaller than the sum of its proper divisors (21625547144).

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

20515304056 is a wasteful number, since it uses less digits than its factorization.

20515304056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6908 (or 6904 counting only the distinct ones).

The product of its (nonzero) digits is 18000, while the sum is 31.

Adding to 20515304056 its reverse (65040351502), we get a palindrome (85555655558).

The spelling of 20515304056 in words is "twenty billion, five hundred fifteen million, three hundred four thousand, fifty-six".