81890732 has 48 divisors (see below), whose sum is σ = 182504448. Its totient is φ = 31221120.

The previous prime is 81890723. The next prime is 81890749. The reversal of 81890732 is 23709818.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 11648 + ... + 17304.

It is an arithmetic number, because the mean of its divisors is an integer number (3802176).

Almost surely, 2^81890732 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81890732, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91252224).

81890732 is an abundant number, since it is smaller than the sum of its proper divisors (100613716).

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

81890732 is a wasteful number, since it uses less digits than its factorization.

81890732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5726 (or 5724 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 81890732 is about 9049.3498108980. The cubic root of 81890732 is about 434.2550901148.

The spelling of 81890732 in words is "eighty-one million, eight hundred ninety thousand, seven hundred thirty-two".