641777760 has 144 divisors (see below), whose sum is σ = 2358602064. Its totient is φ = 157971456.

The previous prime is 641777723. The next prime is 641777783. The reversal of 641777760 is 67777146.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1579 + ... + 35861.

It is an arithmetic number, because the mean of its divisors is an integer number (16379181).

Almost surely, 2^641777760 is an apocalyptic number.

641777760 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 641777760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1179301032).

641777760 is an abundant number, since it is smaller than the sum of its proper divisors (1716824304).

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

641777760 is a wasteful number, since it uses less digits than its factorization.

641777760 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34317 (or 34306 counting only the distinct ones).

The product of its (nonzero) digits is 345744, while the sum is 45.

The square root of 641777760 is about 25333.3329824561. The cubic root of 641777760 is about 862.5710691281.

The spelling of 641777760 in words is "six hundred forty-one million, seven hundred seventy-seven thousand, seven hundred sixty".