21156753956 has 48 divisors (see below), whose sum is σ = 40085559360. Its totient is φ = 9712586880.

The previous prime is 21156753953. The next prime is 21156753971. The reversal of 21156753956 is 65935765112.

It is not an unprimeable number, because it can be changed into a prime (21156753953) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9880646 + ... + 9882786.

It is an arithmetic number, because the mean of its divisors is an integer number (835115820).

Almost surely, 2^21156753956 is an apocalyptic number.

21156753956 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21156753956 is a deficient number, since it is larger than the sum of its proper divisors (18928805404).

21156753956 is a wasteful number, since it uses less digits than its factorization.

21156753956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3084 (or 3082 counting only the distinct ones).

The product of its digits is 1701000, while the sum is 50.

The spelling of 21156753956 in words is "twenty-one billion, one hundred fifty-six million, seven hundred fifty-three thousand, nine hundred fifty-six".