2591131771861 has 4 divisors (see below), whose sum is σ = 2591134991712. Its totient is φ = 2591128552012.

The previous prime is 2591131771841. The next prime is 2591131771897. The reversal of 2591131771861 is 1681771311952.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 2591131771861 - 2¹¹ = 2591131769813 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2591131771799 and 2591131771808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2591131771841) 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, 764526 + ... + 2401408.

It is an arithmetic number, because the mean of its divisors is an integer number (647783747928).

Almost surely, 2^{2591131771861} is an apocalyptic number.

It is an amenable number.

2591131771861 is a deficient number, since it is larger than the sum of its proper divisors (3219851).

2591131771861 is a wasteful number, since it uses less digits than its factorization.

2591131771861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3219850.

The product of its digits is 635040, while the sum is 52.

The spelling of 2591131771861 in words is "two trillion, five hundred ninety-one billion, one hundred thirty-one million, seven hundred seventy-one thousand, eight hundred sixty-one".