640013600 has 144 divisors (see below), whose sum is σ = 1633395456. Its totient is φ = 244608000.

The previous prime is 640013597. The next prime is 640013611. The reversal of 640013600 is 6310046.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3248702 + ... + 3248898.

It is an arithmetic number, because the mean of its divisors is an integer number (11343024).

Almost surely, 2^640013600 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 640013600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (816697728).

640013600 is an abundant number, since it is smaller than the sum of its proper divisors (993381856).

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

640013600 is a wasteful number, since it uses less digits than its factorization.

640013600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 379 (or 366 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 640013600 is about 25298.4900735202. The cubic root of 640013600 is about 861.7799802011.

Adding to 640013600 its reverse (6310046), we get a palindrome (646323646).

The spelling of 640013600 in words is "six hundred forty million, thirteen thousand, six hundred".