640778041904 has 480 divisors, whose sum is σ = 1765414506240. Its totient is φ = 221298739200.

The previous prime is 640778041859. The next prime is 640778041931. The reversal of 640778041904 is 409140877046.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 294068687 + ... + 294070865.

It is an arithmetic number, because the mean of its divisors is an integer number (3677946888).

Almost surely, 2^640778041904 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 640778041904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (882707253120).

640778041904 is an abundant number, since it is smaller than the sum of its proper divisors (1124636464336).

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

640778041904 is a wasteful number, since it uses less digits than its factorization.

640778041904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2329 (or 2316 counting only the distinct ones).

The product of its (nonzero) digits is 1354752, while the sum is 50.

The spelling of 640778041904 in words is "six hundred forty billion, seven hundred seventy-eight million, forty-one thousand, nine hundred four".