21123130125 has 64 divisors (see below), whose sum is σ = 36318896640. Its totient is φ = 10896704000.

The previous prime is 21123130087. The next prime is 21123130153. The reversal of 21123130125 is 52103132112.

It is not a de Polignac number, because 21123130125 - 2⁸ = 21123129869 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1403641 + ... + 1418609.

It is an arithmetic number, because the mean of its divisors is an integer number (567482760).

Almost surely, 2^21123130125 is an apocalyptic number.

21123130125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21123130125 is a deficient number, since it is larger than the sum of its proper divisors (15195766515).

21123130125 is a wasteful number, since it uses less digits than its factorization.

21123130125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15111 (or 15101 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

Adding to 21123130125 its reverse (52103132112), we get a palindrome (73226262237).

The spelling of 21123130125 in words is "twenty-one billion, one hundred twenty-three million, one hundred thirty thousand, one hundred twenty-five".