21876865 has 8 divisors (see below), whose sum is σ = 26363520. Its totient is φ = 17427312.

The previous prime is 21876839. The next prime is 21876871. The reversal of 21876865 is 56867812.

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 21876865 - 2⁷ = 21876737 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7959 + ... + 10348.

It is an arithmetic number, because the mean of its divisors is an integer number (3295440).

Almost surely, 2^21876865 is an apocalyptic number.

It is an amenable number.

21876865 is a deficient number, since it is larger than the sum of its proper divisors (4486655).

21876865 is a wasteful number, since it uses less digits than its factorization.

21876865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18551.

The product of its digits is 161280, while the sum is 43.

The square root of 21876865 is about 4677.2711061045. The cubic root of 21876865 is about 279.6801833131.

The spelling of 21876865 in words is "twenty-one million, eight hundred seventy-six thousand, eight hundred sixty-five".