81739332 has 72 divisors (see below), whose sum is σ = 228324096. Its totient is φ = 24524544.

The previous prime is 81739331. The next prime is 81739337. The reversal of 81739332 is 23393718.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81739331) 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, 11173 + ... + 16979.

It is an arithmetic number, because the mean of its divisors is an integer number (3171168).

Almost surely, 2^81739332 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 81739332, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114162048).

81739332 is an abundant number, since it is smaller than the sum of its proper divisors (146584764).

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

81739332 is a wasteful number, since it uses less digits than its factorization.

81739332 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5857 (or 5852 counting only the distinct ones).

The product of its digits is 27216, while the sum is 36.

The square root of 81739332 is about 9040.9806990171. The cubic root of 81739332 is about 433.9873073511.

The spelling of 81739332 in words is "eighty-one million, seven hundred thirty-nine thousand, three hundred thirty-two".