640766754 has 96 divisors (see below), whose sum is σ = 1592961600. Its totient is φ = 190356480.

The previous prime is 640766741. The next prime is 640766759. The reversal of 640766754 is 457667046.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (640766759) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 295434 + ... + 297594.

It is an arithmetic number, because the mean of its divisors is an integer number (16593350).

Almost surely, 2^640766754 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640766754, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (796480800).

640766754 is an abundant number, since it is smaller than the sum of its proper divisors (952194846).

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

640766754 is a wasteful number, since it uses less digits than its factorization.

640766754 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2225 (or 2202 counting only the distinct ones).

The product of its (nonzero) digits is 846720, while the sum is 45.

The square root of 640766754 is about 25313.3710516794. The cubic root of 640766754 is about 862.1178889624.

The spelling of 640766754 in words is "six hundred forty million, seven hundred sixty-six thousand, seven hundred fifty-four".