20687681925 has 18 divisors (see below), whose sum is σ = 37053937362. Its totient is φ = 11033430240.

The previous prime is 20687681921. The next prime is 20687681941. The reversal of 20687681925 is 52918678602.

It can be written as a sum of positive squares in 3 ways, for example, as 465135489 + 20222546436 = 21567^2 + 142206^2 .

It is not a de Polignac number, because 20687681925 - 2² = 20687681921 is a prime.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20687681921) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 45972402 + ... + 45972851.

Almost surely, 2^20687681925 is an apocalyptic number.

20687681925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20687681925 is a deficient number, since it is larger than the sum of its proper divisors (16366255437).

20687681925 is a wasteful number, since it uses less digits than its factorization.

20687681925 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91945269 (or 91945261 counting only the distinct ones).

The product of its (nonzero) digits is 2903040, while the sum is 54.

The spelling of 20687681925 in words is "twenty billion, six hundred eighty-seven million, six hundred eighty-one thousand, nine hundred twenty-five".