21450664 has 16 divisors (see below), whose sum is σ = 40269600. Its totient is φ = 10712112.

The previous prime is 21450661. The next prime is 21450701. The reversal of 21450664 is 46605412.

It is not an unprimeable number, because it can be changed into a prime (21450661) 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, 10477 + ... + 12355.

It is an arithmetic number, because the mean of its divisors is an integer number (2516850).

Almost surely, 2^21450664 is an apocalyptic number.

It is an amenable number.

21450664 is a deficient number, since it is larger than the sum of its proper divisors (18818936).

21450664 is a wasteful number, since it uses less digits than its factorization.

21450664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3312 (or 3308 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 21450664 is about 4631.4861545728. The cubic root of 21450664 is about 277.8520338132.

The spelling of 21450664 in words is "twenty-one million, four hundred fifty thousand, six hundred sixty-four".