21298864 has 20 divisors (see below), whose sum is σ = 41850000. Its totient is φ = 10498880.

The previous prime is 21298861. The next prime is 21298873. The reversal of 21298864 is 46889212.

It is not an unprimeable number, because it can be changed into a prime (21298861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8239 + ... + 10510.

It is an arithmetic number, because the mean of its divisors is an integer number (2092500).

Almost surely, 2^21298864 is an apocalyptic number.

It is an amenable number.

21298864 is a deficient number, since it is larger than the sum of its proper divisors (20551136).

21298864 is a wasteful number, since it uses less digits than its factorization.

21298864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18828 (or 18822 counting only the distinct ones).

The product of its digits is 55296, while the sum is 40.

The square root of 21298864 is about 4615.0692302500. The cubic root of 21298864 is about 277.1950560875.

The spelling of 21298864 in words is "twenty-one million, two hundred ninety-eight thousand, eight hundred sixty-four".