640165601 has 8 divisors (see below), whose sum is σ = 686053824. Its totient is φ = 595782000.

The previous prime is 640165597. The next prime is 640165621. The reversal of 640165601 is 106561046.

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 640165601 - 2² = 640165597 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (640165621) 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, 375275 + ... + 376976.

It is an arithmetic number, because the mean of its divisors is an integer number (85756728).

Almost surely, 2^640165601 is an apocalyptic number.

It is an amenable number.

640165601 is a deficient number, since it is larger than the sum of its proper divisors (45888223).

640165601 is a wasteful number, since it uses less digits than its factorization.

640165601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 752311.

The product of its (nonzero) digits is 4320, while the sum is 29.

The square root of 640165601 is about 25301.4940467949. The cubic root of 640165601 is about 861.8481980485.

The spelling of 640165601 in words is "six hundred forty million, one hundred sixty-five thousand, six hundred one".