21322987 has 12 divisors (see below), whose sum is σ = 25030296. Its totient is φ = 18110400.

The previous prime is 21322963. The next prime is 21322991. The reversal of 21322987 is 78922312.

It is not a de Polignac number, because 21322987 - 2¹⁵ = 21290219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21322937) 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, 3612 + ... + 7462.

It is an arithmetic number, because the mean of its divisors is an integer number (2085858).

Almost surely, 2^21322987 is an apocalyptic number.

21322987 is a deficient number, since it is larger than the sum of its proper divisors (3707309).

21322987 is a wasteful number, since it uses less digits than its factorization.

21322987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3978 (or 3971 counting only the distinct ones).

The product of its digits is 12096, while the sum is 34.

The square root of 21322987 is about 4617.6819942478. The cubic root of 21322987 is about 277.2996665722.

The spelling of 21322987 in words is "twenty-one million, three hundred twenty-two thousand, nine hundred eighty-seven".