64977391 has 4 divisors (see below), whose sum is σ = 65489152. Its totient is φ = 64465632.

The previous prime is 64977389. The next prime is 64977427. The reversal of 64977391 is 19377946.

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 64977391 - 2¹ = 64977389 is a prime.

It is a super-2 number, since 2×64977391² = 8444122682333762, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64977301) 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, 255690 + ... + 255943.

It is an arithmetic number, because the mean of its divisors is an integer number (16372288).

Almost surely, 2^64977391 is an apocalyptic number.

64977391 is a deficient number, since it is larger than the sum of its proper divisors (511761).

64977391 is a wasteful number, since it uses less digits than its factorization.

64977391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 511760.

The product of its digits is 285768, while the sum is 46.

The square root of 64977391 is about 8060.8554756924. The cubic root of 64977391 is about 402.0259527151.

The spelling of 64977391 in words is "sixty-four million, nine hundred seventy-seven thousand, three hundred ninety-one".