21907879 has 8 divisors (see below), whose sum is σ = 25128320. Its totient is φ = 18710136.

The previous prime is 21907877. The next prime is 21907901. The reversal of 21907879 is 97870912.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21907879 - 2¹ = 21907877 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21907871) 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 7 ways as a sum of consecutive naturals, for example, 3549 + ... + 7510.

It is an arithmetic number, because the mean of its divisors is an integer number (3141040).

Almost surely, 2^21907879 is an apocalyptic number.

21907879 is a deficient number, since it is larger than the sum of its proper divisors (3220441).

21907879 is a wasteful number, since it uses less digits than its factorization.

21907879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11349.

The product of its (nonzero) digits is 63504, while the sum is 43.

The square root of 21907879 is about 4680.5853266445. The cubic root of 21907879 is about 279.8122848961.

The spelling of 21907879 in words is "twenty-one million, nine hundred seven thousand, eight hundred seventy-nine".