21531645153 has 16 divisors (see below), whose sum is σ = 31901707200. Its totient is φ = 14353092000.

The previous prime is 21531645089. The next prime is 21531645173. The reversal of 21531645153 is 35154613512.

21531645153 is a `hidden beast` number, since 2 + 1 + 5 + 3 + 1 + 645 + 1 + 5 + 3 = 666.

It is not a de Polignac number, because 21531645153 - 2⁶ = 21531645089 is a prime.

It is a super-2 number, since 2×21531645153² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21531645173) 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, 320358 + ... + 381696.

It is an arithmetic number, because the mean of its divisors is an integer number (1993856700).

Almost surely, 2^21531645153 is an apocalyptic number.

It is an amenable number.

21531645153 is a deficient number, since it is larger than the sum of its proper divisors (10370062047).

21531645153 is a wasteful number, since it uses less digits than its factorization.

21531645153 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74349 (or 74343 counting only the distinct ones).

The product of its digits is 54000, while the sum is 36.

The spelling of 21531645153 in words is "twenty-one billion, five hundred thirty-one million, six hundred forty-five thousand, one hundred fifty-three".