21604034887 has 2 divisors, whose sum is σ = 21604034888. Its totient is φ = 21604034886.

The previous prime is 21604034831. The next prime is 21604034917. The reversal of 21604034887 is 78843040612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21604034887 - 2³¹ = 19456551239 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21604034087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10802017443 + 10802017444.

It is an arithmetic number, because the mean of its divisors is an integer number (10802017444).

Almost surely, 2^21604034887 is an apocalyptic number.

21604034887 is a deficient number, since it is larger than the sum of its proper divisors (1).

21604034887 is an equidigital number, since it uses as much as digits as its factorization.

21604034887 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 258048, while the sum is 43.

The spelling of 21604034887 in words is "twenty-one billion, six hundred four million, thirty-four thousand, eight hundred eighty-seven".