81177099 has 4 divisors (see below), whose sum is σ = 108236136. Its totient is φ = 54118064.

The previous prime is 81177073. The next prime is 81177113. The reversal of 81177099 is 99077118.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81177099 - 2⁷ = 81176971 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81177099.

It is not an unprimeable number, because it can be changed into a prime (81177049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13529514 + ... + 13529519.

It is an arithmetic number, because the mean of its divisors is an integer number (27059034).

Almost surely, 2^81177099 is an apocalyptic number.

81177099 is a deficient number, since it is larger than the sum of its proper divisors (27059037).

81177099 is a wasteful number, since it uses less digits than its factorization.

81177099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27059036.

The product of its (nonzero) digits is 31752, while the sum is 42.

The square root of 81177099 is about 9009.8334612800. The cubic root of 81177099 is about 432.9899760688.

The spelling of 81177099 in words is "eighty-one million, one hundred seventy-seven thousand, ninety-nine".