81613580 has 12 divisors (see below), whose sum is σ = 171388560. Its totient is φ = 32645424.

The previous prime is 81613561. The next prime is 81613589. The reversal of 81613580 is 8531618.

It is not an unprimeable number, because it can be changed into a prime (81613589) 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, 2040320 + ... + 2040359.

It is an arithmetic number, because the mean of its divisors is an integer number (14282380).

Almost surely, 2^81613580 is an apocalyptic number.

It is an amenable number.

81613580 is an abundant number, since it is smaller than the sum of its proper divisors (89774980).

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

81613580 is a wasteful number, since it uses less digits than its factorization.

81613580 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4080688 (or 4080686 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 32.

The square root of 81613580 is about 9034.0234668723. The cubic root of 81613580 is about 433.7646369778.

The spelling of 81613580 in words is "eighty-one million, six hundred thirteen thousand, five hundred eighty".