81198745 has 8 divisors (see below), whose sum is σ = 97511616. Its totient is φ = 64910256.

The previous prime is 81198731. The next prime is 81198779. The reversal of 81198745 is 54789118.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81198745 - 2⁷ = 81198617 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2284 + ... + 12946.

It is an arithmetic number, because the mean of its divisors is an integer number (12188952).

Almost surely, 2^81198745 is an apocalyptic number.

It is an amenable number.

81198745 is a deficient number, since it is larger than the sum of its proper divisors (16312871).

81198745 is a wasteful number, since it uses less digits than its factorization.

81198745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12191.

The product of its digits is 80640, while the sum is 43.

The square root of 81198745 is about 9011.0346242815. The cubic root of 81198745 is about 433.0284584659.

The spelling of 81198745 in words is "eighty-one million, one hundred ninety-eight thousand, seven hundred forty-five".