131856436721 has 8 divisors (see below), whose sum is σ = 138833866080. Its totient is φ = 124882769088.

The previous prime is 131856436703. The next prime is 131856436739. The reversal of 131856436721 is 127634658131.

It is an interprime number because it is at equal distance from previous prime (131856436703) and next prime (131856436739).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 131856436721 - 2¹⁴ = 131856420337 is a prime.

It is a super-2 number, since 2×131856436721² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (131856436421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 868331 + ... + 1008816.

It is an arithmetic number, because the mean of its divisors is an integer number (17354233260).

Almost surely, 2^131856436721 is an apocalyptic number.

It is an amenable number.

131856436721 is a deficient number, since it is larger than the sum of its proper divisors (6977429359).

131856436721 is a wasteful number, since it uses less digits than its factorization.

131856436721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1880863.

The product of its digits is 725760, while the sum is 47.

The spelling of 131856436721 in words is "one hundred thirty-one billion, eight hundred fifty-six million, four hundred thirty-six thousand, seven hundred twenty-one".