21002475591 has 6 divisors (see below), whose sum is σ = 30336909200. Its totient is φ = 14001650388.

The previous prime is 21002475523. The next prime is 21002475643. The reversal of 21002475591 is 19557420012.

21002475591 is a `hidden beast` number, since 21 + 0 + 0 + 2 + 47 + 5 + 591 = 666.

It is not a de Polignac number, because 21002475591 - 2⁷ = 21002475463 is a prime.

It is a super-2 number, since 2×21002475591² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21002471591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1166804191 + ... + 1166804208.

Almost surely, 2^21002475591 is an apocalyptic number.

21002475591 is a deficient number, since it is larger than the sum of its proper divisors (9334433609).

21002475591 is a wasteful number, since it uses less digits than its factorization.

21002475591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2333608405 (or 2333608402 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 36.

The spelling of 21002475591 in words is "twenty-one billion, two million, four hundred seventy-five thousand, five hundred ninety-one".