640242444 has 48 divisors (see below), whose sum is σ = 1561109760. Its totient is φ = 203839680.

The previous prime is 640242409. The next prime is 640242451. The reversal of 640242444 is 444242046.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 266802 + ... + 269190.

It is an arithmetic number, because the mean of its divisors is an integer number (32523120).

Almost surely, 2^640242444 is an apocalyptic number.

It is an amenable number.

640242444 is an abundant number, since it is smaller than the sum of its proper divisors (920867316).

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

640242444 is a wasteful number, since it uses less digits than its factorization.

640242444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3390 (or 3388 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 30.

The square root of 640242444 is about 25303.0125479161. The cubic root of 640242444 is about 861.8826809756.

The spelling of 640242444 in words is "six hundred forty million, two hundred forty-two thousand, four hundred forty-four".