641772640 has 48 divisors (see below), whose sum is σ = 1517836320. Its totient is φ = 256430080.

The previous prime is 641772629. The next prime is 641772641. The reversal of 641772640 is 46277146.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 641772640.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641772641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 209520 + ... + 212560.

It is an arithmetic number, because the mean of its divisors is an integer number (31621590).

Almost surely, 2^641772640 is an apocalyptic number.

It is an amenable number.

641772640 is an abundant number, since it is smaller than the sum of its proper divisors (876063680).

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

641772640 is a wasteful number, since it uses less digits than its factorization.

641772640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4375 (or 4367 counting only the distinct ones).

The product of its (nonzero) digits is 56448, while the sum is 37.

The square root of 641772640 is about 25333.2319296216. The cubic root of 641772640 is about 862.5687753041.

The spelling of 641772640 in words is "six hundred forty-one million, seven hundred seventy-two thousand, six hundred forty".