21398984 has 16 divisors (see below), whose sum is σ = 41507100. Its totient is φ = 10330432.

The previous prime is 21398957. The next prime is 21398999. The reversal of 21398984 is 48989312.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 21362884 + 36100 = 4622^2 + 190^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45887 + ... + 46350.

Almost surely, 2^21398984 is an apocalyptic number.

It is an amenable number.

21398984 is a deficient number, since it is larger than the sum of its proper divisors (20108116).

21398984 is a wasteful number, since it uses less digits than its factorization.

21398984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92272 (or 92268 counting only the distinct ones).

The product of its digits is 124416, while the sum is 44.

The square root of 21398984 is about 4625.9035874086. The cubic root of 21398984 is about 277.6287160897.

The spelling of 21398984 in words is "twenty-one million, three hundred ninety-eight thousand, nine hundred eighty-four".