81199399 has 8 divisors (see below), whose sum is σ = 82858320. Its totient is φ = 79550016.

The previous prime is 81199397. The next prime is 81199403. The reversal of 81199399 is 99399118.

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 81199399 - 2¹ = 81199397 is a prime.

It is a super-2 number, since 2×81199399² = 13186684795922402, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81199397) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16269 + ... + 20665.

It is an arithmetic number, because the mean of its divisors is an integer number (10357290).

Almost surely, 2^81199399 is an apocalyptic number.

81199399 is a deficient number, since it is larger than the sum of its proper divisors (1658921).

81199399 is a wasteful number, since it uses less digits than its factorization.

81199399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4769.

The product of its digits is 157464, while the sum is 49.

The square root of 81199399 is about 9011.0709130491. The cubic root of 81199399 is about 433.0296210448.

The spelling of 81199399 in words is "eighty-one million, one hundred ninety-nine thousand, three hundred ninety-nine".