81580890 has 32 divisors (see below), whose sum is σ = 200350656. Its totient is φ = 21248640.

The previous prime is 81580879. The next prime is 81580913. The reversal of 81580890 is 9808518.

It is a super-2 number, since 2×81580890² = 13310883226384200, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30331 + ... + 32910.

It is an arithmetic number, because the mean of its divisors is an integer number (6260958).

Almost surely, 2^81580890 is an apocalyptic number.

81580890 is an abundant number, since it is smaller than the sum of its proper divisors (118769766).

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

81580890 is a wasteful number, since it uses less digits than its factorization.

81580890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63294.

The product of its (nonzero) digits is 23040, while the sum is 39.

The square root of 81580890 is about 9032.2140142935. The cubic root of 81580890 is about 433.7067150012.

The spelling of 81580890 in words is "eighty-one million, five hundred eighty thousand, eight hundred ninety".