21153216231 has 32 divisors (see below), whose sum is σ = 35995008000. Its totient is φ = 12026789280.

The previous prime is 21153216199. The next prime is 21153216247. The reversal of 21153216231 is 13261235112.

21153216231 is a `hidden beast` number, since 2 + 1 + 1 + 5 + 32 + 1 + 623 + 1 = 666.

It is not a de Polignac number, because 21153216231 - 2⁵ = 21153216199 is a prime.

It is a super-2 number, since 2×21153216231² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 21153216195 and 21153216204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21153216431) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 243600 + ... + 318821.

It is an arithmetic number, because the mean of its divisors is an integer number (1124844000).

Almost surely, 2^21153216231 is an apocalyptic number.

21153216231 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21153216231 is a deficient number, since it is larger than the sum of its proper divisors (14841791769).

21153216231 is a wasteful number, since it uses less digits than its factorization.

21153216231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 562636 (or 562630 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The spelling of 21153216231 in words is "twenty-one billion, one hundred fifty-three million, two hundred sixteen thousand, two hundred thirty-one".