3261645161681 has 4 divisors (see below), whose sum is σ = 3261658956864. Its totient is φ = 3261631366500.

The previous prime is 3261645161641. The next prime is 3261645161689. The reversal of 3261645161681 is 1861615461623.

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 a de Polignac number, because none of the positive numbers 2^k-3261645161681 is a prime.

It is a super-2 number, since 2×3261645161681² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3261645161689) 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, 6536645 + ... + 7017906.

It is an arithmetic number, because the mean of its divisors is an integer number (815414739216).

Almost surely, 2^{3261645161681} is an apocalyptic number.

It is an amenable number.

3261645161681 is a deficient number, since it is larger than the sum of its proper divisors (13795183).

3261645161681 is a wasteful number, since it uses less digits than its factorization.

3261645161681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13795182.

The product of its digits is 1244160, while the sum is 50.

It can be divided in two parts, 326164 and 5161681, that added together give a palindrome (5487845).

The spelling of 3261645161681 in words is "three trillion, two hundred sixty-one billion, six hundred forty-five million, one hundred sixty-one thousand, six hundred eighty-one".