81205092 has 60 divisors (see below), whose sum is σ = 217499436. Its totient is φ = 26403840.

The previous prime is 81205087. The next prime is 81205093. The reversal of 81205092 is 29050218.

It can be written as a sum of positive squares in 2 ways, for example, as 20738916 + 60466176 = 4554^2 + 7776^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (81205093) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 10228 + ... + 16340.

Almost surely, 2^81205092 is an apocalyptic number.

81205092 is a gapful number since it is divisible by the number (82) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81205092, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108749718).

81205092 is an abundant number, since it is smaller than the sum of its proper divisors (136294344).

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

81205092 is a wasteful number, since it uses less digits than its factorization.

81205092 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6170 (or 6159 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 81205092 is about 9011.3867967145. The cubic root of 81205092 is about 433.0397409064.

The spelling of 81205092 in words is "eighty-one million, two hundred five thousand, ninety-two".