640817616 has 80 divisors (see below), whose sum is σ = 1722810368. Its totient is φ = 205027200.

The previous prime is 640817609. The next prime is 640817621. The reversal of 640817616 is 616718046.

It is a happy number.

It is a congruent number.

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, 187281 + ... + 190671.

Almost surely, 2^640817616 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 640817616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (861405184).

640817616 is an abundant number, since it is smaller than the sum of its proper divisors (1081992752).

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

640817616 is a wasteful number, since it uses less digits than its factorization.

640817616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3560 (or 3554 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 39.

The square root of 640817616 is about 25314.3756786534. The cubic root of 640817616 is about 862.1406990722.

The spelling of 640817616 in words is "six hundred forty million, eight hundred seventeen thousand, six hundred sixteen".