21315494891625 has 64 divisors (see below), whose sum is σ = 38758037760000. Its totient is φ = 10317530808000.

The previous prime is 21315494891599. The next prime is 21315494891627. The reversal of 21315494891625 is 52619849451312.

It is not a de Polignac number, because 21315494891625 - 2¹⁵ = 21315494858857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21315494891627) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1842475 + ... + 6784224.

It is an arithmetic number, because the mean of its divisors is an integer number (605594340000).

Almost surely, 2^{21315494891625} is an apocalyptic number.

21315494891625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21315494891625 is a deficient number, since it is larger than the sum of its proper divisors (17442542868375).

21315494891625 is a wasteful number, since it uses less digits than its factorization.

21315494891625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8627327 (or 8627317 counting only the distinct ones).

The product of its digits is 18662400, while the sum is 60.

The spelling of 21315494891625 in words is "twenty-one trillion, three hundred fifteen billion, four hundred ninety-four million, eight hundred ninety-one thousand, six hundred twenty-five".