21939607 has 2 divisors, whose sum is σ = 21939608. Its totient is φ = 21939606.

The previous prime is 21939581. The next prime is 21939641. The reversal of 21939607 is 70693912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21939607 - 2¹⁵ = 21906839 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21939667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10969803 + 10969804.

It is an arithmetic number, because the mean of its divisors is an integer number (10969804).

Almost surely, 2^21939607 is an apocalyptic number.

21939607 is a deficient number, since it is larger than the sum of its proper divisors (1).

21939607 is an equidigital number, since it uses as much as digits as its factorization.

21939607 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20412, while the sum is 37.

The square root of 21939607 is about 4683.9734200783. The cubic root of 21939607 is about 279.9472987547.

The spelling of 21939607 in words is "twenty-one million, nine hundred thirty-nine thousand, six hundred seven".