81575828 has 12 divisors (see below), whose sum is σ = 143800692. Its totient is φ = 40489920.

The previous prime is 81575827. The next prime is 81575833. The reversal of 81575828 is 82857518.

It can be written as a sum of positive squares in 2 ways, for example, as 23541904 + 58033924 = 4852^2 + 7618^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81575827) 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, 73883 + ... + 74978.

It is an arithmetic number, because the mean of its divisors is an integer number (11983391).

Almost surely, 2^81575828 is an apocalyptic number.

It is an amenable number.

81575828 is a deficient number, since it is larger than the sum of its proper divisors (62224864).

81575828 is a wasteful number, since it uses less digits than its factorization.

81575828 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149002 (or 149000 counting only the distinct ones).

The product of its digits is 179200, while the sum is 44.

The square root of 81575828 is about 9031.9337907228. The cubic root of 81575828 is about 433.6977444820.

The spelling of 81575828 in words is "eighty-one million, five hundred seventy-five thousand, eight hundred twenty-eight".