81072388 has 12 divisors (see below), whose sum is σ = 150222492. Its totient is φ = 38151680.

The previous prime is 81072379. The next prime is 81072403. The reversal of 81072388 is 88327018.

It can be written as a sum of positive squares in 2 ways, for example, as 26193924 + 54878464 = 5118^2 + 7408^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 596053 + ... + 596188.

It is an arithmetic number, because the mean of its divisors is an integer number (12518541).

Almost surely, 2^81072388 is an apocalyptic number.

It is an amenable number.

81072388 is a deficient number, since it is larger than the sum of its proper divisors (69150104).

81072388 is a wasteful number, since it uses less digits than its factorization.

81072388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1192262 (or 1192260 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 37.

The square root of 81072388 is about 9004.0206574619. The cubic root of 81072388 is about 432.8037235328.

The spelling of 81072388 in words is "eighty-one million, seventy-two thousand, three hundred eighty-eight".