21702987 has 12 divisors (see below), whose sum is σ = 31463224. Its totient is φ = 14415840.

The previous prime is 21702983. The next prime is 21703009. The reversal of 21702987 is 78920712.

It is not a de Polignac number, because 21702987 - 2² = 21702983 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21702983) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1714 + ... + 6807.

Almost surely, 2^21702987 is an apocalyptic number.

21702987 is a deficient number, since it is larger than the sum of its proper divisors (9760237).

21702987 is a wasteful number, since it uses less digits than its factorization.

21702987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8810 (or 8807 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 21702987 is about 4658.6464772507. The cubic root of 21702987 is about 278.9372426002.

The spelling of 21702987 in words is "twenty-one million, seven hundred two thousand, nine hundred eighty-seven".