64974991 has 4 divisors (see below), whose sum is σ = 64999000. Its totient is φ = 64950984.

The previous prime is 64974983. The next prime is 64975007. The reversal of 64974991 is 19947946.

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 64974991 - 2³ = 64974983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64974911) 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 in 3 ways as a sum of consecutive naturals, for example, 7341 + ... + 13558.

It is an arithmetic number, because the mean of its divisors is an integer number (16249750).

Almost surely, 2^64974991 is an apocalyptic number.

64974991 is a deficient number, since it is larger than the sum of its proper divisors (24009).

64974991 is a wasteful number, since it uses less digits than its factorization.

64974991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24008.

The product of its digits is 489888, while the sum is 49.

The square root of 64974991 is about 8060.7066067436. The cubic root of 64974991 is about 402.0210029207.

The spelling of 64974991 in words is "sixty-four million, nine hundred seventy-four thousand, nine hundred ninety-one".