21245984 has 12 divisors (see below), whose sum is σ = 41828094. Its totient is φ = 10622976.

The previous prime is 21245981. The next prime is 21246053. The reversal of 21245984 is 48954212.

It can be written as a sum of positive squares in only one way, i.e., 19114384 + 2131600 = 4372^2 + 1460^2 .

It is a super-2 number, since 2×21245984² = 902783672256512, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21245981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 331937 + ... + 332000.

Almost surely, 2^21245984 is an apocalyptic number.

It is an amenable number.

21245984 is a deficient number, since it is larger than the sum of its proper divisors (20582110).

21245984 is an equidigital number, since it uses as much as digits as its factorization.

21245984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 663947 (or 663939 counting only the distinct ones).

The product of its digits is 23040, while the sum is 35.

The square root of 21245984 is about 4609.3366117046. The cubic root of 21245984 is about 276.9654629011.

The spelling of 21245984 in words is "twenty-one million, two hundred forty-five thousand, nine hundred eighty-four".