81565092 has 144 divisors (see below), whose sum is σ = 249080832. Its totient is φ = 22014720.

The previous prime is 81565079. The next prime is 81565093. The reversal of 81565092 is 29056518.

It is a happy number.

81565092 is a `hidden beast` number, since 8 + 1 + 565 + 0 + 92 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (81565093) 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 47 ways as a sum of consecutive naturals, for example, 413938 + ... + 414134.

It is an arithmetic number, because the mean of its divisors is an integer number (1729728).

Almost surely, 2^81565092 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81565092, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124540416).

81565092 is an abundant number, since it is smaller than the sum of its proper divisors (167515740).

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

81565092 is a wasteful number, since it uses less digits than its factorization.

81565092 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 298 (or 293 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 36.

The square root of 81565092 is about 9031.3394355433. The cubic root of 81565092 is about 433.6787176724.

The spelling of 81565092 in words is "eighty-one million, five hundred sixty-five thousand, ninety-two".