641345261 has 4 divisors (see below), whose sum is σ = 644385024. Its totient is φ = 638305500.

The previous prime is 641345219. The next prime is 641345273. The reversal of 641345261 is 162543146.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 641345261 - 2²² = 637150957 is a prime.

It is a super-2 number, since 2×641345261² = 822647487614316242, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (641345291) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1519565 + ... + 1519986.

It is an arithmetic number, because the mean of its divisors is an integer number (161096256).

Almost surely, 2^641345261 is an apocalyptic number.

It is an amenable number.

641345261 is a deficient number, since it is larger than the sum of its proper divisors (3039763).

641345261 is a wasteful number, since it uses less digits than its factorization.

641345261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3039762.

The product of its digits is 17280, while the sum is 32.

The square root of 641345261 is about 25324.7953792326. The cubic root of 641345261 is about 862.3772611453.

The spelling of 641345261 in words is "six hundred forty-one million, three hundred forty-five thousand, two hundred sixty-one".