21606364187 has 2 divisors, whose sum is σ = 21606364188. Its totient is φ = 21606364186.

The previous prime is 21606364181. The next prime is 21606364259. The reversal of 21606364187 is 78146360612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21606364187 - 2³² = 17311396891 is a prime.

It is not a weakly prime, because it can be changed into another prime (21606364181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10803182093 + 10803182094.

It is an arithmetic number, because the mean of its divisors is an integer number (10803182094).

Almost surely, 2^21606364187 is an apocalyptic number.

21606364187 is a deficient number, since it is larger than the sum of its proper divisors (1).

21606364187 is an equidigital number, since it uses as much as digits as its factorization.

21606364187 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 290304, while the sum is 44.

The spelling of 21606364187 in words is "twenty-one billion, six hundred six million, three hundred sixty-four thousand, one hundred eighty-seven".