21856649234 has 48 divisors (see below), whose sum is σ = 38996755200. Its totient is φ = 9158438016.

The previous prime is 21856649149. The next prime is 21856649239. The reversal of 21856649234 is 43294665812.

It is a super-2 number, since 2×21856649234² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21856649239) 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, 783722 + ... + 811130.

It is an arithmetic number, because the mean of its divisors is an integer number (812432400).

Almost surely, 2^21856649234 is an apocalyptic number.

21856649234 is a deficient number, since it is larger than the sum of its proper divisors (17140105966).

21856649234 is a wasteful number, since it uses less digits than its factorization.

21856649234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27607 (or 27600 counting only the distinct ones).

The product of its digits is 2488320, while the sum is 50.

The spelling of 21856649234 in words is "twenty-one billion, eight hundred fifty-six million, six hundred forty-nine thousand, two hundred thirty-four".