81959199 has 8 divisors (see below), whose sum is σ = 124890240. Its totient is φ = 46833816.

The previous prime is 81959149. The next prime is 81959203. The reversal of 81959199 is 99195918.

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

It is not a de Polignac number, because 81959199 - 2⁹ = 81958687 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81959149) 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, 1951389 + ... + 1951430.

It is an arithmetic number, because the mean of its divisors is an integer number (15611280).

Almost surely, 2^81959199 is an apocalyptic number.

81959199 is a deficient number, since it is larger than the sum of its proper divisors (42931041).

81959199 is a wasteful number, since it uses less digits than its factorization.

81959199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3902829.

The product of its digits is 262440, while the sum is 51.

The square root of 81959199 is about 9053.1319994795. The cubic root of 81959199 is about 434.3760800415.

The spelling of 81959199 in words is "eighty-one million, nine hundred fifty-nine thousand, one hundred ninety-nine".