81582305 has 12 divisors (see below), whose sum is σ = 113882580. Its totient is φ = 55941984.

The previous prime is 81582289. The next prime is 81582323. The reversal of 81582305 is 50328518.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 44408896 + 37173409 = 6664^2 + 6097^2 .

It is not a de Polignac number, because 81582305 - 2⁴ = 81582289 is a prime.

It is a super-2 number, since 2×81582305² = 13311344978226050, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 166250 + ... + 166739.

It is an arithmetic number, because the mean of its divisors is an integer number (9490215).

Almost surely, 2^81582305 is an apocalyptic number.

It is an amenable number.

81582305 is a deficient number, since it is larger than the sum of its proper divisors (32300275).

81582305 is a wasteful number, since it uses less digits than its factorization.

81582305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333008 (or 333001 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 32.

The square root of 81582305 is about 9032.2923446930. The cubic root of 81582305 is about 433.7092224979.

The spelling of 81582305 in words is "eighty-one million, five hundred eighty-two thousand, three hundred five".