21863687 has 4 divisors (see below), whose sum is σ = 21884280. Its totient is φ = 21843096.

The previous prime is 21863671. The next prime is 21863713. The reversal of 21863687 is 78636812.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21863687 - 2⁴ = 21863671 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 (21863617) 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 3 ways as a sum of consecutive naturals, for example, 8612 + ... + 10857.

It is an arithmetic number, because the mean of its divisors is an integer number (5471070).

Almost surely, 2^21863687 is an apocalyptic number.

21863687 is a deficient number, since it is larger than the sum of its proper divisors (20593).

21863687 is a wasteful number, since it uses less digits than its factorization.

21863687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20592.

The product of its digits is 96768, while the sum is 41.

The square root of 21863687 is about 4675.8621664887. The cubic root of 21863687 is about 279.6240149096.

The spelling of 21863687 in words is "twenty-one million, eight hundred sixty-three thousand, six hundred eighty-seven".