131999261 has 2 divisors, whose sum is σ = 131999262. Its totient is φ = 131999260.

The previous prime is 131999233. The next prime is 131999267. The reversal of 131999261 is 162999131.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83083225 + 48916036 = 9115^2 + 6994^2 .

It is an emirp because it is prime and its reverse (162999131) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 131999261 - 2¹⁸ = 131737117 is a prime.

It is a super-2 number, since 2×131999261² = 34847609809092242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131999267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65999630 + 65999631.

It is an arithmetic number, because the mean of its divisors is an integer number (65999631).

Almost surely, 2^131999261 is an apocalyptic number.

It is an amenable number.

131999261 is a deficient number, since it is larger than the sum of its proper divisors (1).

131999261 is an equidigital number, since it uses as much as digits as its factorization.

131999261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26244, while the sum is 41.

The square root of 131999261 is about 11489.0931321841. The cubic root of 131999261 is about 509.1633867812.

The spelling of 131999261 in words is "one hundred thirty-one million, nine hundred ninety-nine thousand, two hundred sixty-one".