21876789 has 16 divisors (see below), whose sum is σ = 31901184. Its totient is φ = 13225200.

The previous prime is 21876781. The next prime is 21876791. The reversal of 21876789 is 98767812.

It is not a de Polignac number, because 21876789 - 2³ = 21876781 is a prime.

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21876781) 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, 20704 + ... + 21734.

It is an arithmetic number, because the mean of its divisors is an integer number (1993824).

Almost surely, 2^21876789 is an apocalyptic number.

It is an amenable number.

21876789 is a deficient number, since it is larger than the sum of its proper divisors (10024395).

21876789 is a wasteful number, since it uses less digits than its factorization.

21876789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1688.

The product of its digits is 338688, while the sum is 48.

The square root of 21876789 is about 4677.2629817020. The cubic root of 21876789 is about 279.6798594440.

The spelling of 21876789 in words is "twenty-one million, eight hundred seventy-six thousand, seven hundred eighty-nine".