640741671 has 12 divisors (see below), whose sum is σ = 959794472. Its totient is φ = 427160952.

The previous prime is 640741643. The next prime is 640741681. The reversal of 640741671 is 176147046.

640741671 is a `hidden beast` number, since 640 + 7 + 4 + 1 + 6 + 7 + 1 = 666.

It is not a de Polignac number, because 640741671 - 2¹⁷ = 640610599 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 (640741601) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1318156 + ... + 1318641.

Almost surely, 2^640741671 is an apocalyptic number.

640741671 is a deficient number, since it is larger than the sum of its proper divisors (319052801).

640741671 is an equidigital number, since it uses as much as digits as its factorization.

640741671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2636812 (or 2636800 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 36.

The square root of 640741671 is about 25312.8755972134. The cubic root of 640741671 is about 862.1066395309.

The spelling of 640741671 in words is "six hundred forty million, seven hundred forty-one thousand, six hundred seventy-one".