21317457125 has 16 divisors (see below), whose sum is σ = 26978904576. Its totient is φ = 16813762000.

The previous prime is 21317457121. The next prime is 21317457143. The reversal of 21317457125 is 52175471312.

It is not a de Polignac number, because 21317457125 - 2² = 21317457121 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21317457121) 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, 1192109 + ... + 1209858.

It is an arithmetic number, because the mean of its divisors is an integer number (1686181536).

Almost surely, 2^21317457125 is an apocalyptic number.

21317457125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21317457125 is a deficient number, since it is larger than the sum of its proper divisors (5661447451).

21317457125 is an equidigital number, since it uses as much as digits as its factorization.

21317457125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2402053 (or 2402043 counting only the distinct ones).

The product of its digits is 58800, while the sum is 38.

The spelling of 21317457125 in words is "twenty-one billion, three hundred seventeen million, four hundred fifty-seven thousand, one hundred twenty-five".