640513896 has 128 divisors (see below), whose sum is σ = 1893196800. Its totient is φ = 178375680.

The previous prime is 640513891. The next prime is 640513897. The reversal of 640513896 is 698315046.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (640513891) 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, 191325 + ... + 194643.

It is an arithmetic number, because the mean of its divisors is an integer number (14790600).

Almost surely, 2^640513896 is an apocalyptic number.

640513896 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640513896, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (946598400).

640513896 is an abundant number, since it is smaller than the sum of its proper divisors (1252682904).

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

640513896 is a wasteful number, since it uses less digits than its factorization.

640513896 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3399 (or 3395 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 42.

The square root of 640513896 is about 25308.3760047934. The cubic root of 640513896 is about 862.0044716725.

It can be divided in two parts, 6405 and 13896, that added together give a triangular number (20301 = T₂₀₁).

The spelling of 640513896 in words is "six hundred forty million, five hundred thirteen thousand, eight hundred ninety-six".