81230820 has 48 divisors (see below), whose sum is σ = 248125248. Its totient is φ = 19692160.

The previous prime is 81230813. The next prime is 81230837. The reversal of 81230820 is 2803218.

It is a super-2 number, since 2×81230820² = 13196892235744800, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 60879 + ... + 62198.

It is an arithmetic number, because the mean of its divisors is an integer number (5169276).

Almost surely, 2^81230820 is an apocalyptic number.

It is an amenable number.

81230820 is an abundant number, since it is smaller than the sum of its proper divisors (166894428).

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

81230820 is a wasteful number, since it uses less digits than its factorization.

81230820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123100 (or 123098 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 81230820 is about 9012.8142108888. The cubic root of 81230820 is about 433.0854690324.

The spelling of 81230820 in words is "eighty-one million, two hundred thirty thousand, eight hundred twenty".