661131576271 has 4 divisors (see below), whose sum is σ = 682458401344. Its totient is φ = 639804751200.

The previous prime is 661131576251. The next prime is 661131576311. The reversal of 661131576271 is 172675131166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661131576271 - 2⁵ = 661131576239 is a prime.

It is a super-2 number, since 2×661131576271² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661131576251) 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, 10663412490 + ... + 10663412551.

It is an arithmetic number, because the mean of its divisors is an integer number (170614600336).

Almost surely, 2^661131576271 is an apocalyptic number.

661131576271 is a deficient number, since it is larger than the sum of its proper divisors (21326825073).

661131576271 is a wasteful number, since it uses less digits than its factorization.

661131576271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21326825072.

The product of its digits is 317520, while the sum is 46.

The spelling of 661131576271 in words is "six hundred sixty-one billion, one hundred thirty-one million, five hundred seventy-six thousand, two hundred seventy-one".