131521961 has 4 divisors (see below), whose sum is σ = 131544912. Its totient is φ = 131499012.

The previous prime is 131521921. The next prime is 131521963. The reversal of 131521961 is 169125131.

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, and also an emirpimes, since its reverse is a distinct semiprime: 169125131 = 7 ⋅24160733.

It is a cyclic number.

It is not a de Polignac number, because 131521961 - 2¹⁰ = 131520937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (131521963) 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, 5150 + ... + 17016.

It is an arithmetic number, because the mean of its divisors is an integer number (32886228).

Almost surely, 2^131521961 is an apocalyptic number.

It is an amenable number.

131521961 is a deficient number, since it is larger than the sum of its proper divisors (22951).

131521961 is a wasteful number, since it uses less digits than its factorization.

131521961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22950.

The product of its digits is 1620, while the sum is 29.

The square root of 131521961 is about 11468.3024463083. The cubic root of 131521961 is about 508.5489459848.

The spelling of 131521961 in words is "one hundred thirty-one million, five hundred twenty-one thousand, nine hundred sixty-one".