131556233721 has 12 divisors (see below), whose sum is σ = 192804177776. Its totient is φ = 79731050520.

The previous prime is 131556233701. The next prime is 131556233749. The reversal of 131556233721 is 127332655131.

It is not a de Polignac number, because 131556233721 - 2⁶ = 131556233657 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 131556233721.

It is not an unprimeable number, because it can be changed into a prime (131556233701) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 181206571 + ... + 181207296.

Almost surely, 2^131556233721 is an apocalyptic number.

131556233721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

131556233721 is a deficient number, since it is larger than the sum of its proper divisors (61247944055).

131556233721 is a wasteful number, since it uses less digits than its factorization.

131556233721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362413892 (or 362413881 counting only the distinct ones).

The product of its digits is 113400, while the sum is 39.

Adding to 131556233721 its reverse (127332655131), we get a palindrome (258888888852).

The spelling of 131556233721 in words is "one hundred thirty-one billion, five hundred fifty-six million, two hundred thirty-three thousand, seven hundred twenty-one".