81550392 has 64 divisors (see below), whose sum is σ = 254188800. Its totient is φ = 21181440.

The previous prime is 81550379. The next prime is 81550393. The reversal of 81550392 is 29305518.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81550393) 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 15 ways as a sum of consecutive naturals, for example, 20217 + ... + 23912.

It is an arithmetic number, because the mean of its divisors is an integer number (3971700).

Almost surely, 2^81550392 is an apocalyptic number.

It is an amenable number.

81550392 is an abundant number, since it is smaller than the sum of its proper divisors (172638408).

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

81550392 is a wasteful number, since it uses less digits than its factorization.

81550392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44156 (or 44152 counting only the distinct ones).

The product of its (nonzero) digits is 10800, while the sum is 33.

The square root of 81550392 is about 9030.5255661008. The cubic root of 81550392 is about 433.6526629799.

The spelling of 81550392 in words is "eighty-one million, five hundred fifty thousand, three hundred ninety-two".