64939999 has 4 divisors (see below), whose sum is σ = 66165336. Its totient is φ = 63714664.

The previous prime is 64939993. The next prime is 64940021. The reversal of 64939999 is 99993946.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 64939999 - 2²⁵ = 31385567 is a prime.

It is a Duffinian number.

64939999 is a modest number, since divided by 9999 gives 6493 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64939993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 612589 + ... + 612694.

It is an arithmetic number, because the mean of its divisors is an integer number (16541334).

Almost surely, 2^64939999 is an apocalyptic number.

64939999 is a deficient number, since it is larger than the sum of its proper divisors (1225337).

64939999 is a wasteful number, since it uses less digits than its factorization.

64939999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1225336.

The product of its digits is 4251528, while the sum is 58.

The square root of 64939999 is about 8058.5357851163. The cubic root of 64939999 is about 401.9488210714.

The spelling of 64939999 in words is "sixty-four million, nine hundred thirty-nine thousand, nine hundred ninety-nine".