641731980 has 96 divisors (see below), whose sum is σ = 1908252864. Its totient is φ = 160579584.

The previous prime is 641731949. The next prime is 641731991. The reversal of 641731980 is 89137146.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 440934 + ... + 442386.

It is an arithmetic number, because the mean of its divisors is an integer number (19877634).

Almost surely, 2^641731980 is an apocalyptic number.

641731980 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 641731980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (954126432).

641731980 is an abundant number, since it is smaller than the sum of its proper divisors (1266520884).

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

641731980 is a wasteful number, since it uses less digits than its factorization.

641731980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1915 (or 1913 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 39.

The square root of 641731980 is about 25332.4294136982. The cubic root of 641731980 is about 862.5505586830.

The spelling of 641731980 in words is "six hundred forty-one million, seven hundred thirty-one thousand, nine hundred eighty".