21987707 has 8 divisors (see below), whose sum is σ = 25555200. Its totient is φ = 18526824.

The previous prime is 21987703. The next prime is 21987727. The reversal of 21987707 is 70778912.

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 21987707 - 2² = 21987703 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21987703) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26207 + ... + 27032.

It is an arithmetic number, because the mean of its divisors is an integer number (3194400).

Almost surely, 2^21987707 is an apocalyptic number.

21987707 is a deficient number, since it is larger than the sum of its proper divisors (3567493).

21987707 is an equidigital number, since it uses as much as digits as its factorization.

21987707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53305.

The product of its (nonzero) digits is 49392, while the sum is 41.

The square root of 21987707 is about 4689.1051385099. The cubic root of 21987707 is about 280.1517332364.

The spelling of 21987707 in words is "twenty-one million, nine hundred eighty-seven thousand, seven hundred seven".