640271394 has 24 divisors (see below), whose sum is σ = 1585434240. Its totient is φ = 182934648.

The previous prime is 640271377. The next prime is 640271407. The reversal of 640271394 is 493172046.

640271394 is a `hidden beast` number, since 640 + 2 + 7 + 1 + 3 + 9 + 4 = 666.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2540634 + ... + 2540885.

It is an arithmetic number, because the mean of its divisors is an integer number (66059760).

Almost surely, 2^640271394 is an apocalyptic number.

640271394 is an abundant number, since it is smaller than the sum of its proper divisors (945162846).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

640271394 is a wasteful number, since it uses less digits than its factorization.

640271394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5081534 (or 5081531 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

The square root of 640271394 is about 25303.5846077191. The cubic root of 640271394 is about 861.8956714335.

The spelling of 640271394 in words is "six hundred forty million, two hundred seventy-one thousand, three hundred ninety-four".