81557275 has 12 divisors (see below), whose sum is σ = 101270304. Its totient is φ = 65156000.

The previous prime is 81557257. The next prime is 81557297. The reversal of 81557275 is 57275518.

It is not a de Polignac number, because 81557275 - 2⁵ = 81557243 is a prime.

It is a Duffinian number.

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, 20985 + ... + 24565.

It is an arithmetic number, because the mean of its divisors is an integer number (8439192).

Almost surely, 2^81557275 is an apocalyptic number.

81557275 is a deficient number, since it is larger than the sum of its proper divisors (19713029).

81557275 is a wasteful number, since it uses less digits than its factorization.

81557275 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4502 (or 4497 counting only the distinct ones).

The product of its digits is 98000, while the sum is 40.

The square root of 81557275 is about 9030.9066543731. The cubic root of 81557275 is about 433.6648629920.

The spelling of 81557275 in words is "eighty-one million, five hundred fifty-seven thousand, two hundred seventy-five".