641720881 has 8 divisors (see below), whose sum is σ = 651153824. Its totient is φ = 632305440.

The previous prime is 641720869. The next prime is 641720887. The reversal of 641720881 is 188027146.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 641720881 - 2⁷ = 641720753 is a prime.

It is a super-2 number, since 2×641720881² = 823611378222832322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 641720881.

It is not an unprimeable number, because it can be changed into a prime (641720887) 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, 81730 + ... + 89236.

It is an arithmetic number, because the mean of its divisors is an integer number (81394228).

Almost surely, 2^641720881 is an apocalyptic number.

It is an amenable number.

641720881 is a deficient number, since it is larger than the sum of its proper divisors (9432943).

641720881 is a wasteful number, since it uses less digits than its factorization.

641720881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8751.

The product of its (nonzero) digits is 21504, while the sum is 37.

The square root of 641720881 is about 25332.2103457239. The cubic root of 641720881 is about 862.5455859404.

The spelling of 641720881 in words is "six hundred forty-one million, seven hundred twenty thousand, eight hundred eighty-one".