21256669488 has 20 divisors (see below), whose sum is σ = 54913062968. Its totient is φ = 7085556480.

The previous prime is 21256669471. The next prime is 21256669537. The reversal of 21256669488 is 88496665212.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 221423593 + ... + 221423688.

Almost surely, 2^21256669488 is an apocalyptic number.

It is an amenable number.

21256669488 is an abundant number, since it is smaller than the sum of its proper divisors (33656393480).

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

21256669488 is a wasteful number, since it uses less digits than its factorization.

21256669488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 442847292 (or 442847286 counting only the distinct ones).

The product of its digits is 9953280, while the sum is 57.

The spelling of 21256669488 in words is "twenty-one billion, two hundred fifty-six million, six hundred sixty-nine thousand, four hundred eighty-eight".