21125921598 has 24 divisors (see below), whose sum is σ = 47009935128. Its totient is φ = 6851650032.

The previous prime is 21125921581. The next prime is 21125921669. The reversal of 21125921598 is 89512952112.

It is a happy number.

21125921598 is a `hidden beast` number, since 2 + 1 + 1 + 2 + 59 + 2 + 1 + 598 = 666.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15859636 + ... + 15860967.

It is an arithmetic number, because the mean of its divisors is an integer number (1958747297).

Almost surely, 2^21125921598 is an apocalyptic number.

21125921598 is an abundant number, since it is smaller than the sum of its proper divisors (25884013530).

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

21125921598 is a wasteful number, since it uses less digits than its factorization.

21125921598 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31720648 (or 31720645 counting only the distinct ones).

The product of its digits is 129600, while the sum is 45.

The spelling of 21125921598 in words is "twenty-one billion, one hundred twenty-five million, nine hundred twenty-one thousand, five hundred ninety-eight".