21251103536 has 40 divisors (see below), whose sum is σ = 44875513200. Its totient is φ = 9690022656.

The previous prime is 21251103493. The next prime is 21251103547. The reversal of 21251103536 is 63530115212.

It is a junction number, because it is equal to n+sod(n) for n = 21251103499 and 21251103508.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 598211 + ... + 632738.

It is an arithmetic number, because the mean of its divisors is an integer number (1121887830).

Almost surely, 2^21251103536 is an apocalyptic number.

21251103536 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21251103536 is an abundant number, since it is smaller than the sum of its proper divisors (23624409664).

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

21251103536 is a wasteful number, since it uses less digits than its factorization.

21251103536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1231053 (or 1231047 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 29.

Adding to 21251103536 its reverse (63530115212), we get a palindrome (84781218748).

The spelling of 21251103536 in words is "twenty-one billion, two hundred fifty-one million, one hundred three thousand, five hundred thirty-six".