131694721 has 2 divisors, whose sum is σ = 131694722. Its totient is φ = 131694720.

The previous prime is 131694707. The next prime is 131694743. The reversal of 131694721 is 127496131.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 127238400 + 4456321 = 11280^2 + 2111^2 .

It is a cyclic number.

It is not a de Polignac number, because 131694721 - 2⁷ = 131694593 is a prime.

It is not a weakly prime, because it can be changed into another prime (131694751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65847360 + 65847361.

It is an arithmetic number, because the mean of its divisors is an integer number (65847361).

Almost surely, 2^131694721 is an apocalyptic number.

It is an amenable number.

131694721 is a deficient number, since it is larger than the sum of its proper divisors (1).

131694721 is an equidigital number, since it uses as much as digits as its factorization.

131694721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9072, while the sum is 34.

The square root of 131694721 is about 11475.8320395516. The cubic root of 131694721 is about 508.7715158514.

The spelling of 131694721 in words is "one hundred thirty-one million, six hundred ninety-four thousand, seven hundred twenty-one".