640441356 has 12 divisors (see below), whose sum is σ = 1494363192. Its totient is φ = 213480448.

The previous prime is 640441339. The next prime is 640441393. The reversal of 640441356 is 653144046.

It is a tau number, because it is divible by the number of its divisors (12).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26685045 + ... + 26685068.

It is an arithmetic number, because the mean of its divisors is an integer number (124530266).

Almost surely, 2^640441356 is an apocalyptic number.

It is an amenable number.

640441356 is an abundant number, since it is smaller than the sum of its proper divisors (853921836).

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

640441356 is a wasteful number, since it uses less digits than its factorization.

640441356 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53370120 (or 53370118 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 33.

The square root of 640441356 is about 25306.9428418369. The cubic root of 640441356 is about 861.9719289671.

The spelling of 640441356 in words is "six hundred forty million, four hundred forty-one thousand, three hundred fifty-six".