25166116521 has 24 divisors (see below), whose sum is σ = 44739764160. Its totient is φ = 13274434656.

The previous prime is 25166116513. The next prime is 25166116649. The reversal of 25166116521 is 12561166152.

25166116521 is a `hidden beast` number, since 2 + 5 + 16 + 6 + 116 + 521 = 666.

It is not a de Polignac number, because 25166116521 - 2³ = 25166116513 is a prime.

It is a super-4 number, since 4×25166116521⁴ (a number of 43 digits) contains 4444 as substring.

It is not an unprimeable number, because it can be changed into a prime (25166116321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15363111 + ... + 15364748.

It is an arithmetic number, because the mean of its divisors is an integer number (1864156840).

Almost surely, 2^25166116521 is an apocalyptic number.

25166116521 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

25166116521 is a deficient number, since it is larger than the sum of its proper divisors (19573647639).

25166116521 is a wasteful number, since it uses less digits than its factorization.

25166116521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30727885 (or 30727882 counting only the distinct ones).

The product of its digits is 21600, while the sum is 36.

The spelling of 25166116521 in words is "twenty-five billion, one hundred sixty-six million, one hundred sixteen thousand, five hundred twenty-one".