21867887 has 4 divisors (see below), whose sum is σ = 21879240. Its totient is φ = 21856536.

The previous prime is 21867869. The next prime is 21867913. The reversal of 21867887 is 78876812.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21867887 - 2⁶ = 21867823 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21867487) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1988 + ... + 6905.

It is an arithmetic number, because the mean of its divisors is an integer number (5469810).

Almost surely, 2^21867887 is an apocalyptic number.

21867887 is a deficient number, since it is larger than the sum of its proper divisors (11353).

21867887 is an equidigital number, since it uses as much as digits as its factorization.

21867887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11352.

The product of its digits is 301056, while the sum is 47.

The square root of 21867887 is about 4676.3112599569. The cubic root of 21867887 is about 279.6419189601.

The spelling of 21867887 in words is "twenty-one million, eight hundred sixty-seven thousand, eight hundred eighty-seven".