64439839 has 2 divisors, whose sum is σ = 64439840. Its totient is φ = 64439838.

The previous prime is 64439803. The next prime is 64439861. The reversal of 64439839 is 93893446.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 64439839 - 2¹⁵ = 64407071 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64439899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32219919 + 32219920.

It is an arithmetic number, because the mean of its divisors is an integer number (32219920).

Almost surely, 2^64439839 is an apocalyptic number.

64439839 is a deficient number, since it is larger than the sum of its proper divisors (1).

64439839 is an equidigital number, since it uses as much as digits as its factorization.

64439839 is an evil number, because the sum of its binary digits is even.

The product of its digits is 559872, while the sum is 46.

The square root of 64439839 is about 8027.4428680620. The cubic root of 64439839 is about 400.9142400707.

The spelling of 64439839 in words is "sixty-four million, four hundred thirty-nine thousand, eight hundred thirty-nine".