81799197 has 4 divisors (see below), whose sum is σ = 109065600. Its totient is φ = 54532796.

The previous prime is 81799187. The next prime is 81799213. The reversal of 81799197 is 79199718.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81799197 - 2⁴ = 81799181 is a prime.

It is a super-2 number, since 2×81799197² = 13382217259689618, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81799177) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13633197 + ... + 13633202.

It is an arithmetic number, because the mean of its divisors is an integer number (27266400).

Almost surely, 2^81799197 is an apocalyptic number.

It is an amenable number.

81799197 is a deficient number, since it is larger than the sum of its proper divisors (27266403).

81799197 is a wasteful number, since it uses less digits than its factorization.

81799197 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27266402.

The product of its digits is 285768, while the sum is 51.

The square root of 81799197 is about 9044.2908511392. The cubic root of 81799197 is about 434.0932306948.

The spelling of 81799197 in words is "eighty-one million, seven hundred ninety-nine thousand, one hundred ninety-seven".