64839919 has 2 divisors, whose sum is σ = 64839920. Its totient is φ = 64839918.

The previous prime is 64839917. The next prime is 64839923. The reversal of 64839919 is 91993846.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 64839919 - 2¹ = 64839917 is a prime.

It is a super-2 number, since 2×64839919² = 8408430191853122, which contains 22 as substring.

Together with 64839917, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (64839917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32419959 + 32419960.

It is an arithmetic number, because the mean of its divisors is an integer number (32419960).

Almost surely, 2^64839919 is an apocalyptic number.

64839919 is a deficient number, since it is larger than the sum of its proper divisors (1).

64839919 is an equidigital number, since it uses as much as digits as its factorization.

64839919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 419904, while the sum is 49.

The square root of 64839919 is about 8052.3238260765. The cubic root of 64839919 is about 401.7422318035.

The spelling of 64839919 in words is "sixty-four million, eight hundred thirty-nine thousand, nine hundred nineteen".