21154768186 has 16 divisors (see below), whose sum is σ = 31796093160. Its totient is φ = 10556089600.

The previous prime is 21154768183. The next prime is 21154768211. The reversal of 21154768186 is 68186745112.

It can be written as a sum of positive squares in 4 ways, for example, as 21139706025 + 15062161 = 145395^2 + 3881^2 .

It is not an unprimeable number, because it can be changed into a prime (21154768183) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3217110 + ... + 3223678.

Almost surely, 2^21154768186 is an apocalyptic number.

21154768186 is a deficient number, since it is larger than the sum of its proper divisors (10641324974).

21154768186 is a wasteful number, since it uses less digits than its factorization.

21154768186 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9569.

The product of its digits is 645120, while the sum is 49.

The spelling of 21154768186 in words is "twenty-one billion, one hundred fifty-four million, seven hundred sixty-eight thousand, one hundred eighty-six".