81097573 has 4 divisors (see below), whose sum is σ = 81122860. Its totient is φ = 81072288.

The previous prime is 81097507. The next prime is 81097619. The reversal of 81097573 is 37579018.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 49028004 + 32069569 = 7002^2 + 5663^2 .

It is a cyclic number.

It is not a de Polignac number, because 81097573 - 2⁹ = 81097061 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81091573) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6990 + ... + 14527.

It is an arithmetic number, because the mean of its divisors is an integer number (20280715).

Almost surely, 2^81097573 is an apocalyptic number.

It is an amenable number.

81097573 is a deficient number, since it is larger than the sum of its proper divisors (25287).

81097573 is a wasteful number, since it uses less digits than its factorization.

81097573 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25286.

The product of its (nonzero) digits is 52920, while the sum is 40.

The square root of 81097573 is about 9005.4190907475. The cubic root of 81097573 is about 432.8485354740.

The spelling of 81097573 in words is "eighty-one million, ninety-seven thousand, five hundred seventy-three".