21105680591925 has 30 divisors (see below), whose sum is σ = 39095016250818. Its totient is φ = 11256362981280.

The previous prime is 21105680591923. The next prime is 21105680591927. The reversal of 21105680591925 is 52919508650112.

21105680591925 is a `hidden beast` number, since 2 + 1 + 1 + 0 + 568 + 0 + 59 + 1 + 9 + 25 = 666.

It is an interprime number because it is at equal distance from previous prime (21105680591923) and next prime (21105680591927).

It can be written as a sum of positive squares in 3 ways, for example, as 1913369496516 + 19192311095409 = 1383246^2 + 4380903^2 .

It is not a de Polignac number, because 21105680591925 - 2¹ = 21105680591923 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21105680591923) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 5211277134 + ... + 5211281183.

Almost surely, 2^{21105680591925} is an apocalyptic number.

21105680591925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21105680591925 is a deficient number, since it is larger than the sum of its proper divisors (17989335658893).

21105680591925 is a wasteful number, since it uses less digits than its factorization.

21105680591925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10422558339 (or 10422558325 counting only the distinct ones).

The product of its (nonzero) digits is 1944000, while the sum is 54.

The spelling of 21105680591925 in words is "twenty-one trillion, one hundred five billion, six hundred eighty million, five hundred ninety-one thousand, nine hundred twenty-five".