131506021 has 2 divisors, whose sum is σ = 131506022. Its totient is φ = 131506020.

The previous prime is 131506013. The next prime is 131506031. The reversal of 131506021 is 120605131.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 96530625 + 34975396 = 9825^2 + 5914^2 .

It is an emirp because it is prime and its reverse (120605131) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 131506021 - 2³ = 131506013 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 131506021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131506031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65753010 + 65753011.

It is an arithmetic number, because the mean of its divisors is an integer number (65753011).

Almost surely, 2^131506021 is an apocalyptic number.

It is an amenable number.

131506021 is a deficient number, since it is larger than the sum of its proper divisors (1).

131506021 is an equidigital number, since it uses as much as digits as its factorization.

131506021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 131506021 is about 11467.6074662503. The cubic root of 131506021 is about 508.5284003723.

The spelling of 131506021 in words is "one hundred thirty-one million, five hundred six thousand, twenty-one".