640997448 has 128 divisors (see below), whose sum is σ = 1988689920. Its totient is φ = 167650560.

The previous prime is 640997387. The next prime is 640997449. The reversal of 640997448 is 844799046.

It is a self number, because there is not a number n which added to its sum of digits gives 640997448.

It is not an unprimeable number, because it can be changed into a prime (640997449) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 276213 + ... + 278523.

It is an arithmetic number, because the mean of its divisors is an integer number (15536640).

Almost surely, 2^640997448 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640997448, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (994344960).

640997448 is an abundant number, since it is smaller than the sum of its proper divisors (1347692472).

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

640997448 is a wasteful number, since it uses less digits than its factorization.

640997448 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2467 (or 2463 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 51.

The square root of 640997448 is about 25317.9274033243. The cubic root of 640997448 is about 862.2213387538.

The spelling of 640997448 in words is "six hundred forty million, nine hundred ninety-seven thousand, four hundred forty-eight".