664527391 has 8 divisors (see below), whose sum is σ = 728736768. Its totient is φ = 600951000.

The previous prime is 664527361. The next prime is 664527397. The reversal of 664527391 is 193725466.

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

It is a cyclic number.

It is not a de Polignac number, because 664527391 - 2⁵ = 664527359 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 (664527397) 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, 156045 + ... + 160246.

It is an arithmetic number, because the mean of its divisors is an integer number (91092096).

Almost surely, 2^664527391 is an apocalyptic number.

664527391 is a deficient number, since it is larger than the sum of its proper divisors (64209377).

664527391 is a wasteful number, since it uses less digits than its factorization.

664527391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316493.

The product of its digits is 272160, while the sum is 43.

The square root of 664527391 is about 25778.4287923062. The cubic root of 664527391 is about 872.6450487498.

The spelling of 664527391 in words is "six hundred sixty-four million, five hundred twenty-seven thousand, three hundred ninety-one".