81028580 has 12 divisors (see below), whose sum is σ = 170160060. Its totient is φ = 32411424.

The previous prime is 81028561. The next prime is 81028583. The reversal of 81028580 is 8582018.

It can be written as a sum of positive squares in 2 ways, for example, as 12503296 + 68525284 = 3536^2 + 8278^2 .

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (81028583) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2025695 + ... + 2025734.

It is an arithmetic number, because the mean of its divisors is an integer number (14180005).

Almost surely, 2^81028580 is an apocalyptic number.

It is an amenable number.

81028580 is an abundant number, since it is smaller than the sum of its proper divisors (89131480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81028580 is a wasteful number, since it uses less digits than its factorization.

81028580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4051438 (or 4051436 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 32.

The square root of 81028580 is about 9001.5876377448. The cubic root of 81028580 is about 432.7257533709.

The spelling of 81028580 in words is "eighty-one million, twenty-eight thousand, five hundred eighty".