641815890 has 32 divisors (see below), whose sum is σ = 1545302016. Its totient is φ = 170601600.

The previous prime is 641815883. The next prime is 641815901. The reversal of 641815890 is 98518146.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24786 + ... + 43565.

It is an arithmetic number, because the mean of its divisors is an integer number (48290688).

Almost surely, 2^641815890 is an apocalyptic number.

641815890 is an abundant number, since it is smaller than the sum of its proper divisors (903486126).

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

641815890 is a wasteful number, since it uses less digits than its factorization.

641815890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68674.

The product of its (nonzero) digits is 69120, while the sum is 42.

The square root of 641815890 is about 25334.0855370783. The cubic root of 641815890 is about 862.5881514607.

The spelling of 641815890 in words is "six hundred forty-one million, eight hundred fifteen thousand, eight hundred ninety".