21372887 has 2 divisors, whose sum is σ = 21372888. Its totient is φ = 21372886.

The previous prime is 21372839. The next prime is 21372889. The reversal of 21372887 is 78827312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21372887 - 2¹² = 21368791 is a prime.

Together with 21372889, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21372887.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21372889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10686443 + 10686444.

It is an arithmetic number, because the mean of its divisors is an integer number (10686444).

Almost surely, 2^21372887 is an apocalyptic number.

21372887 is a deficient number, since it is larger than the sum of its proper divisors (1).

21372887 is an equidigital number, since it uses as much as digits as its factorization.

21372887 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 37632, while the sum is 38.

The square root of 21372887 is about 4623.0819806705. The cubic root of 21372887 is about 277.5158100453.

The spelling of 21372887 in words is "twenty-one million, three hundred seventy-two thousand, eight hundred eighty-seven".