664065731 has 8 divisors (see below), whose sum is σ = 759531360. Its totient is φ = 568749888.

The previous prime is 664065691. The next prime is 664065737. The reversal of 664065731 is 137560466.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-664065731 is a prime.

It is a super-2 number, since 2×664065731² = 881966590177128722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (664065737) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27776 + ... + 45821.

It is an arithmetic number, because the mean of its divisors is an integer number (94941420).

Almost surely, 2^664065731 is an apocalyptic number.

664065731 is a deficient number, since it is larger than the sum of its proper divisors (95465629).

664065731 is a wasteful number, since it uses less digits than its factorization.

664065731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74893.

The product of its (nonzero) digits is 90720, while the sum is 38.

The square root of 664065731 is about 25769.4728506425. The cubic root of 664065731 is about 872.4429208177.

The spelling of 664065731 in words is "six hundred sixty-four million, sixty-five thousand, seven hundred thirty-one".