81167913 has 10 divisors (see below), whose sum is σ = 121250954. Its totient is φ = 54111888.

The previous prime is 81167909. The next prime is 81167923. The reversal of 81167913 is 31976118.

It can be written as a sum of positive squares in only one way, i.e., 47155689 + 34012224 = 6867^2 + 5832^2 .

It is not a de Polignac number, because 81167913 - 2² = 81167909 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81167903) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 500956 + ... + 501117.

Almost surely, 2^81167913 is an apocalyptic number.

It is an amenable number.

81167913 is a deficient number, since it is larger than the sum of its proper divisors (40083041).

81167913 is a wasteful number, since it uses less digits than its factorization.

81167913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1002085 (or 1002076 counting only the distinct ones).

The product of its digits is 9072, while the sum is 36.

The square root of 81167913 is about 9009.3236705093. The cubic root of 81167913 is about 432.9736430717.

The spelling of 81167913 in words is "eighty-one million, one hundred sixty-seven thousand, nine hundred thirteen".