81292273924 has 9 divisors (see below), whose sum is σ = 142262477287. Its totient is φ = 40645851844.

The previous prime is 81292273913. The next prime is 81292273961. The reversal of 81292273924 is 42937229218.

The square root of 81292273924 is 285118.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 498957 + ... + 641515.

Almost surely, 2^81292273924 is an apocalyptic number.

81292273924 is the 285118-th square number.

It is an amenable number.

81292273924 is a deficient number, since it is larger than the sum of its proper divisors (60970203363).

81292273924 is an frugal number, since it uses more digits than its factorization.

81292273924 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285122 (or 142561 counting only the distinct ones).

The product of its digits is 870912, while the sum is 49.

Multiplying 81292273924 by its sum of digits (49), we get a square (3983321422276 = 1995826²).

It can be divided in two parts, 81292 and 273924, that added together give a square (355216 = 596²).

The spelling of 81292273924 in words is "eighty-one billion, two hundred ninety-two million, two hundred seventy-three thousand, nine hundred twenty-four".