81919192 has 32 divisors (see below), whose sum is σ = 169711200. Its totient is φ = 36872704.

The previous prime is 81919183. The next prime is 81919193. The reversal of 81919192 is 29191918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81919193) by changing a digit.

It is an upside-down number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9967 + ... + 16222.

It is an arithmetic number, because the mean of its divisors is an integer number (5303475).

Almost surely, 2^81919192 is an apocalyptic number.

It is an amenable number.

81919192 is an abundant number, since it is smaller than the sum of its proper divisors (87792008).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81919192 is a wasteful number, since it uses less digits than its factorization.

81919192 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26235 (or 26231 counting only the distinct ones).

The product of its digits is 11664, while the sum is 40.

The square root of 81919192 is about 9050.9221629622. The cubic root of 81919192 is about 434.3053907537.

The spelling of 81919192 in words is "eighty-one million, nine hundred nineteen thousand, one hundred ninety-two".