131556521 has 4 divisors (see below), whose sum is σ = 132720852. Its totient is φ = 130392192.

The previous prime is 131556517. The next prime is 131556533. The reversal of 131556521 is 125655131.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 125655131 = 7 ⋅17950733.

It can be written as a sum of positive squares in 2 ways, for example, as 1345600 + 130210921 = 1160^2 + 11411^2 .

It is a cyclic number.

It is not a de Polignac number, because 131556521 - 2² = 131556517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (131556511) 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, 581996 + ... + 582221.

It is an arithmetic number, because the mean of its divisors is an integer number (33180213).

Almost surely, 2^131556521 is an apocalyptic number.

It is an amenable number.

131556521 is a deficient number, since it is larger than the sum of its proper divisors (1164331).

131556521 is a wasteful number, since it uses less digits than its factorization.

131556521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1164330.

The product of its digits is 4500, while the sum is 29.

The square root of 131556521 is about 11469.8091091352. The cubic root of 131556521 is about 508.5934858528.

The spelling of 131556521 in words is "one hundred thirty-one million, five hundred fifty-six thousand, five hundred twenty-one".