21554656187 has 2 divisors, whose sum is σ = 21554656188. Its totient is φ = 21554656186.

The previous prime is 21554656177. The next prime is 21554656213. The reversal of 21554656187 is 78165645512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21554656187 - 2³² = 17259688891 is a prime.

It is not a weakly prime, because it can be changed into another prime (21554656127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10777328093 + 10777328094.

It is an arithmetic number, because the mean of its divisors is an integer number (10777328094).

Almost surely, 2^21554656187 is an apocalyptic number.

21554656187 is a deficient number, since it is larger than the sum of its proper divisors (1).

21554656187 is an equidigital number, since it uses as much as digits as its factorization.

21554656187 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2016000, while the sum is 50.

The spelling of 21554656187 in words is "twenty-one billion, five hundred fifty-four million, six hundred fifty-six thousand, one hundred eighty-seven".