81057872285 has 16 divisors (see below), whose sum is σ = 107582842416. Its totient is φ = 58240332288.

The previous prime is 81057872281. The next prime is 81057872303. The reversal of 81057872285 is 58227875018.

It can be written as a sum of positive squares in 8 ways, for example, as 1338608569 + 79719263716 = 36587^2 + 282346^2 .

It is a cyclic number.

It is not a de Polignac number, because 81057872285 - 2² = 81057872281 is a prime.

It is a super-2 number, since 2×81057872285² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81057872281) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16849544 + ... + 16854353.

It is an arithmetic number, because the mean of its divisors is an integer number (6723927651).

Almost surely, 2^81057872285 is an apocalyptic number.

It is an amenable number.

81057872285 is a deficient number, since it is larger than the sum of its proper divisors (26524970131).

81057872285 is a wasteful number, since it uses less digits than its factorization.

81057872285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33703952.

The product of its (nonzero) digits is 2508800, while the sum is 53.

The spelling of 81057872285 in words is "eighty-one billion, fifty-seven million, eight hundred seventy-two thousand, two hundred eighty-five".