81975892 has 12 divisors (see below), whose sum is σ = 146957076. Its totient is φ = 39988160.

The previous prime is 81975871. The next prime is 81975893. The reversal of 81975892 is 29857918.

It can be written as a sum of positive squares in 2 ways, for example, as 49758916 + 32216976 = 7054^2 + 5676^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81975893) 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, 249763 + ... + 250090.

It is an arithmetic number, because the mean of its divisors is an integer number (12246423).

Almost surely, 2^81975892 is an apocalyptic number.

81975892 is a gapful number since it is divisible by the number (82) formed by its first and last digit.

It is an amenable number.

81975892 is a deficient number, since it is larger than the sum of its proper divisors (64981184).

81975892 is a wasteful number, since it uses less digits than its factorization.

81975892 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 499898 (or 499896 counting only the distinct ones).

The product of its digits is 362880, while the sum is 49.

The square root of 81975892 is about 9054.0538986688. The cubic root of 81975892 is about 434.4055684852.

The spelling of 81975892 in words is "eighty-one million, nine hundred seventy-five thousand, eight hundred ninety-two".