640768271 has 8 divisors (see below), whose sum is σ = 752790864. Its totient is φ = 537707520.

The previous prime is 640768243. The next prime is 640768273. The reversal of 640768271 is 172867046.

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 640768271 - 2⁶ = 640768207 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 (640768273) 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, 2240306 + ... + 2240591.

It is an arithmetic number, because the mean of its divisors is an integer number (94098858).

Almost surely, 2^640768271 is an apocalyptic number.

640768271 is a deficient number, since it is larger than the sum of its proper divisors (112022593).

640768271 is a wasteful number, since it uses less digits than its factorization.

640768271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4480921.

The product of its (nonzero) digits is 112896, while the sum is 41.

The square root of 640768271 is about 25313.4010160626. The cubic root of 640768271 is about 862.1185693098.

The spelling of 640768271 in words is "six hundred forty million, seven hundred sixty-eight thousand, two hundred seventy-one".