81580842 has 48 divisors (see below), whose sum is σ = 202517952. Its totient is φ = 23250240.

The previous prime is 81580823. The next prime is 81580843. The reversal of 81580842 is 24808518.

It is a junction number, because it is equal to n+sod(n) for n = 81580797 and 81580806.

It is not an unprimeable number, because it can be changed into a prime (81580843) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 86598 + ... + 87534.

It is an arithmetic number, because the mean of its divisors is an integer number (4219124).

Almost surely, 2^81580842 is an apocalyptic number.

81580842 is an abundant number, since it is smaller than the sum of its proper divisors (120937110).

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

81580842 is a wasteful number, since it uses less digits than its factorization.

81580842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1643 (or 1640 counting only the distinct ones).

The product of its (nonzero) digits is 20480, while the sum is 36.

The square root of 81580842 is about 9032.2113571373. The cubic root of 81580842 is about 433.7066299407.

The spelling of 81580842 in words is "eighty-one million, five hundred eighty thousand, eight hundred forty-two".