641661911 has 6 divisors (see below), whose sum is σ = 705297936. Its totient is φ = 583328900.

The previous prime is 641661883. The next prime is 641661971. The reversal of 641661911 is 119166146.

It is not a de Polignac number, because 641661911 - 2¹⁸ = 641399767 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641661971) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2651375 + ... + 2651616.

It is an arithmetic number, because the mean of its divisors is an integer number (117549656).

Almost surely, 2^641661911 is an apocalyptic number.

641661911 is a deficient number, since it is larger than the sum of its proper divisors (63636025).

641661911 is a wasteful number, since it uses less digits than its factorization.

641661911 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5303013 (or 5303002 counting only the distinct ones).

The product of its digits is 7776, while the sum is 35.

The square root of 641661911 is about 25331.0463858089. The cubic root of 641661911 is about 862.5191643435.

The spelling of 641661911 in words is "six hundred forty-one million, six hundred sixty-one thousand, nine hundred eleven".