21438064 has 20 divisors (see below), whose sum is σ = 41724760. Its totient is φ = 10670400.

The previous prime is 21438049. The next prime is 21438073. The reversal of 21438064 is 46083412.

It is a congruent number.

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, 739 + ... + 6589.

It is an arithmetic number, because the mean of its divisors is an integer number (2086238).

Almost surely, 2^21438064 is an apocalyptic number.

It is an amenable number.

21438064 is a deficient number, since it is larger than the sum of its proper divisors (20286696).

21438064 is a wasteful number, since it uses less digits than its factorization.

21438064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6088 (or 6082 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 21438064 is about 4630.1257002375. The cubic root of 21438064 is about 277.7976202477.

The spelling of 21438064 in words is "twenty-one million, four hundred thirty-eight thousand, sixty-four".