21064464 has 60 divisors (see below), whose sum is σ = 62062000. Its totient is φ = 6651072.

The previous prime is 21064363. The next prime is 21064471. The reversal of 21064464 is 46446012.

21064464 is a `hidden beast` number, since 2 + 10 + 644 + 6 + 4 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1114 + ... + 6585.

Almost surely, 2^21064464 is an apocalyptic number.

21064464 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21064464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31031000).

21064464 is an abundant number, since it is smaller than the sum of its proper divisors (40997536).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21064464 is a wasteful number, since it uses less digits than its factorization.

21064464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7732 (or 7723 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

The square root of 21064464 is about 4589.6039044780. The cubic root of 21064464 is about 276.1744328978.

It can be divided in two parts, 21064 and 464, that added together give a triangular number (21528 = T₂₀₇).

The spelling of 21064464 in words is "twenty-one million, sixty-four thousand, four hundred sixty-four".