21064479 has 16 divisors (see below), whose sum is σ = 30303072. Its totient is φ = 12965888.

The previous prime is 21064471. The next prime is 21064499. The reversal of 21064479 is 97446012.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21064479 - 2³ = 21064471 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21064471) 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 15 ways as a sum of consecutive naturals, for example, 1194 + ... + 6599.

It is an arithmetic number, because the mean of its divisors is an integer number (1893942).

Almost surely, 2^21064479 is an apocalyptic number.

21064479 is a deficient number, since it is larger than the sum of its proper divisors (9238593).

21064479 is a wasteful number, since it uses less digits than its factorization.

21064479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7866.

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 21064479 is about 4589.6055386057. The cubic root of 21064479 is about 276.1744984524.

The spelling of 21064479 in words is "twenty-one million, sixty-four thousand, four hundred seventy-nine".