640251954 has 24 divisors (see below), whose sum is σ = 1416729600. Its totient is φ = 208876248.

The previous prime is 640251923. The next prime is 640251971. The reversal of 640251954 is 459152046.

640251954 is a `hidden beast` number, since 640 + 2 + 5 + 1 + 9 + 5 + 4 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 377554 + ... + 379245.

It is an arithmetic number, because the mean of its divisors is an integer number (59030400).

Almost surely, 2^640251954 is an apocalyptic number.

640251954 is an abundant number, since it is smaller than the sum of its proper divisors (776477646).

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

640251954 is a wasteful number, since it uses less digits than its factorization.

640251954 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 756854 (or 756851 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 36.

The square root of 640251954 is about 25303.2004695058. The cubic root of 640251954 is about 861.8869483506.

The spelling of 640251954 in words is "six hundred forty million, two hundred fifty-one thousand, nine hundred fifty-four".