21486987 has 12 divisors (see below), whose sum is σ = 31196880. Its totient is φ = 14250768.

The previous prime is 21486977. The next prime is 21486989. The reversal of 21486987 is 78968412.

It is not a de Polignac number, because 21486987 - 2⁶ = 21486923 is a prime.

It is a super-2 number, since 2×21486987² = 923381220676338, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21486989) 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, 4287 + ... + 7832.

It is an arithmetic number, because the mean of its divisors is an integer number (2599740).

Almost surely, 2^21486987 is an apocalyptic number.

21486987 is a deficient number, since it is larger than the sum of its proper divisors (9709893).

21486987 is a wasteful number, since it uses less digits than its factorization.

21486987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12322 (or 12319 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 21486987 is about 4635.4058074779. The cubic root of 21486987 is about 278.0087768738.

The spelling of 21486987 in words is "twenty-one million, four hundred eighty-six thousand, nine hundred eighty-seven".