20531351256 has 64 divisors (see below), whose sum is σ = 55344733920. Its totient is φ = 6309565440.

The previous prime is 20531351233. The next prime is 20531351273. The reversal of 20531351256 is 65215313502.

It is a happy number.

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, 216076 + ... + 296228.

Almost surely, 2^20531351256 is an apocalyptic number.

20531351256 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 20531351256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27672366960).

20531351256 is an abundant number, since it is smaller than the sum of its proper divisors (34813382664).

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

20531351256 is a wasteful number, since it uses less digits than its factorization.

20531351256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80996 (or 80992 counting only the distinct ones).

The product of its (nonzero) digits is 27000, while the sum is 33.

Adding to 20531351256 its reverse (65215313502), we get a palindrome (85746664758).

The spelling of 20531351256 in words is "twenty billion, five hundred thirty-one million, three hundred fifty-one thousand, two hundred fifty-six".