21876387 has 16 divisors (see below), whose sum is σ = 31557120. Its totient is φ = 13400352.

The previous prime is 21876377. The next prime is 21876389. The reversal of 21876387 is 78367812.

It is not a de Polignac number, because 21876387 - 2¹⁰ = 21875363 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (21876389) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8148 + ... + 10494.

It is an arithmetic number, because the mean of its divisors is an integer number (1972320).

Almost surely, 2^21876387 is an apocalyptic number.

21876387 is a deficient number, since it is larger than the sum of its proper divisors (9680733).

21876387 is a wasteful number, since it uses less digits than its factorization.

21876387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2602.

The product of its digits is 112896, while the sum is 42.

The square root of 21876387 is about 4677.2200076541. The cubic root of 21876387 is about 279.6781463347.

The spelling of 21876387 in words is "twenty-one million, eight hundred seventy-six thousand, three hundred eighty-seven".