21376691 has 12 divisors (see below), whose sum is σ = 26176680. Its totient is φ = 17357760.

The previous prime is 21376687. The next prime is 21376721. The reversal of 21376691 is 19667312.

It is not a de Polignac number, because 21376691 - 2² = 21376687 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21376601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10550 + ... + 12411.

It is an arithmetic number, because the mean of its divisors is an integer number (2181390).

Almost surely, 2^21376691 is an apocalyptic number.

21376691 is a deficient number, since it is larger than the sum of its proper divisors (4799989).

21376691 is a wasteful number, since it uses less digits than its factorization.

21376691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22994 (or 22987 counting only the distinct ones).

The product of its digits is 13608, while the sum is 35.

The square root of 21376691 is about 4623.4933762254. The cubic root of 21376691 is about 277.5322733885.

The spelling of 21376691 in words is "twenty-one million, three hundred seventy-six thousand, six hundred ninety-one".