640738448 has 40 divisors (see below), whose sum is σ = 1423896960. Its totient is φ = 273611520.

The previous prime is 640738433. The next prime is 640738457. The reversal of 640738448 is 844837046.

It is a junction number, because it is equal to n+sod(n) for n = 640738399 and 640738408.

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 7 ways as a sum of consecutive naturals, for example, 21293 + ... + 41651.

It is an arithmetic number, because the mean of its divisors is an integer number (35597424).

Almost surely, 2^640738448 is an apocalyptic number.

It is an amenable number.

640738448 is an abundant number, since it is smaller than the sum of its proper divisors (783158512).

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

640738448 is a wasteful number, since it uses less digits than its factorization.

640738448 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20655 (or 20649 counting only the distinct ones).

The product of its (nonzero) digits is 516096, while the sum is 44.

The square root of 640738448 is about 25312.8119338804. The cubic root of 640738448 is about 862.1051940319.

The spelling of 640738448 in words is "six hundred forty million, seven hundred thirty-eight thousand, four hundred forty-eight".