81399190 has 8 divisors (see below), whose sum is σ = 146518560. Its totient is φ = 32559672.

The previous prime is 81399187. The next prime is 81399191. The reversal of 81399190 is 9199318.

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

It is a super-2 number, since 2×81399190² = 13251656265312200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81399191) 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, 4069950 + ... + 4069969.

It is an arithmetic number, because the mean of its divisors is an integer number (18314820).

Almost surely, 2^81399190 is an apocalyptic number.

81399190 is a deficient number, since it is larger than the sum of its proper divisors (65119370).

81399190 is a wasteful number, since it uses less digits than its factorization.

81399190 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8139926.

The product of its (nonzero) digits is 17496, while the sum is 40.

The square root of 81399190 is about 9022.1499655016. The cubic root of 81399190 is about 433.3844864006.

The spelling of 81399190 in words is "eighty-one million, three hundred ninety-nine thousand, one hundred ninety".