64640397 has 8 divisors (see below), whose sum is σ = 86495040. Its totient is φ = 42939680.

The previous prime is 64640393. The next prime is 64640399. The reversal of 64640397 is 79304646.

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 64640397 - 2² = 64640393 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64640393) 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, 37497 + ... + 39182.

It is an arithmetic number, because the mean of its divisors is an integer number (10811880).

Almost surely, 2^64640397 is an apocalyptic number.

It is an amenable number.

64640397 is a deficient number, since it is larger than the sum of its proper divisors (21854643).

64640397 is a wasteful number, since it uses less digits than its factorization.

64640397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76963.

The product of its (nonzero) digits is 108864, while the sum is 39.

The square root of 64640397 is about 8039.9251862191. The cubic root of 64640397 is about 401.3297350301.

The spelling of 64640397 in words is "sixty-four million, six hundred forty thousand, three hundred ninety-seven".