21907867 has 2 divisors, whose sum is σ = 21907868. Its totient is φ = 21907866.

The previous prime is 21907841. The next prime is 21907871. The reversal of 21907867 is 76870912.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21907867 is a prime.

It is not a weakly prime, because it can be changed into another prime (21907877) 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 as a sum of consecutive naturals, namely, 10953933 + 10953934.

It is an arithmetic number, because the mean of its divisors is an integer number (10953934).

Almost surely, 2^21907867 is an apocalyptic number.

21907867 is a deficient number, since it is larger than the sum of its proper divisors (1).

21907867 is an equidigital number, since it uses as much as digits as its factorization.

21907867 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 21907867 is about 4680.5840447534. The cubic root of 21907867 is about 279.8122338072.

The spelling of 21907867 in words is "twenty-one million, nine hundred seven thousand, eight hundred sixty-seven".