640290642 has 16 divisors (see below), whose sum is σ = 1293015360. Its totient is φ = 211357872.

The previous prime is 640290617. The next prime is 640290649. The reversal of 640290642 is 246092046.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (640290649) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 517417 + ... + 518652.

It is an arithmetic number, because the mean of its divisors is an integer number (80813460).

Almost surely, 2^640290642 is an apocalyptic number.

640290642 is an abundant number, since it is smaller than the sum of its proper divisors (652724718).

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

640290642 is a wasteful number, since it uses less digits than its factorization.

640290642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1036177.

The product of its (nonzero) digits is 20736, while the sum is 33.

The square root of 640290642 is about 25303.9649462293. The cubic root of 640290642 is about 861.9043081886.

The spelling of 640290642 in words is "six hundred forty million, two hundred ninety thousand, six hundred forty-two".