81912244 has 6 divisors (see below), whose sum is σ = 143346434. Its totient is φ = 40956120.

The previous prime is 81912241. The next prime is 81912247. The reversal of 81912244 is 44221918.

It is an interprime number because it is at equal distance from previous prime (81912241) and next prime (81912247).

It can be written as a sum of positive squares in only one way, i.e., 61027344 + 20884900 = 7812^2 + 4570^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81912241) 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 as a sum of consecutive naturals, namely, 10239027 + ... + 10239034.

Almost surely, 2^81912244 is an apocalyptic number.

It is an amenable number.

81912244 is a deficient number, since it is larger than the sum of its proper divisors (61434190).

81912244 is a wasteful number, since it uses less digits than its factorization.

81912244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20478065 (or 20478063 counting only the distinct ones).

The product of its digits is 4608, while the sum is 31.

The square root of 81912244 is about 9050.5383265306. The cubic root of 81912244 is about 434.2931118274.

The spelling of 81912244 in words is "eighty-one million, nine hundred twelve thousand, two hundred forty-four".