640370961 has 8 divisors (see below), whose sum is σ = 948697760. Its totient is φ = 426913956.

The previous prime is 640370903. The next prime is 640370987. The reversal of 640370961 is 169073046.

640370961 is a `hidden beast` number, since 640 + 3 + 7 + 0 + 9 + 6 + 1 = 666.

It is not a de Polignac number, because 640370961 - 2⁶ = 640370897 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 (640370461) 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, 11858695 + ... + 11858748.

It is an arithmetic number, because the mean of its divisors is an integer number (118587220).

Almost surely, 2^640370961 is an apocalyptic number.

It is an amenable number.

640370961 is a deficient number, since it is larger than the sum of its proper divisors (308326799).

640370961 is a wasteful number, since it uses less digits than its factorization.

640370961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23717452 (or 23717446 counting only the distinct ones).

The product of its (nonzero) digits is 27216, while the sum is 36.

The square root of 640370961 is about 25305.5519797534. The cubic root of 640370961 is about 861.9403461965.

The spelling of 640370961 in words is "six hundred forty million, three hundred seventy thousand, nine hundred sixty-one".