641041661 has 8 divisors (see below), whose sum is σ = 730961784. Its totient is φ = 556922880.

The previous prime is 641041573. The next prime is 641041663. The reversal of 641041661 is 166140146.

It can be written as a sum of positive squares in 4 ways, for example, as 648025 + 640393636 = 805^2 + 25306^2 .

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 641041661 - 2¹⁴ = 641025277 is a prime.

It is a super-2 number, since 2×641041661² = 821868822275277842, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641041663) 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, 1450100 + ... + 1450541.

It is an arithmetic number, because the mean of its divisors is an integer number (91370223).

Almost surely, 2^641041661 is an apocalyptic number.

It is an amenable number.

641041661 is a deficient number, since it is larger than the sum of its proper divisors (89920123).

641041661 is a wasteful number, since it uses less digits than its factorization.

641041661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2900671.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 641041661 is about 25318.8005442596. The cubic root of 641041661 is about 862.2411622937.

The spelling of 641041661 in words is "six hundred forty-one million, forty-one thousand, six hundred sixty-one".