640097440 has 48 divisors (see below), whose sum is σ = 1523823840. Its totient is φ = 254076160.

The previous prime is 640097387. The next prime is 640097449. The reversal of 640097440 is 44790046.

It is a junction number, because it is equal to n+sod(n) for n = 640097396 and 640097405.

It is not an unprimeable number, because it can be changed into a prime (640097449) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5691 + ... + 36229.

It is an arithmetic number, because the mean of its divisors is an integer number (31746330).

Almost surely, 2^640097440 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 640097440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (761911920).

640097440 is an abundant number, since it is smaller than the sum of its proper divisors (883726400).

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

640097440 is a wasteful number, since it uses less digits than its factorization.

640097440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30685 (or 30677 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 34.

The square root of 640097440 is about 25300.1470351459. The cubic root of 640097440 is about 861.8176088176.

The spelling of 640097440 in words is "six hundred forty million, ninety-seven thousand, four hundred forty".