81731376 has 160 divisors (see below), whose sum is σ = 257126400. Its totient is φ = 24744960.

The previous prime is 81731341. The next prime is 81731381. The reversal of 81731376 is 67313718.

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

It is a self number, because there is not a number n which added to its sum of digits gives 81731376.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 227485 + ... + 227843.

It is an arithmetic number, because the mean of its divisors is an integer number (1607040).

Almost surely, 2^81731376 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 81731376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (128563200).

81731376 is an abundant number, since it is smaller than the sum of its proper divisors (175395024).

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

81731376 is a wasteful number, since it uses less digits than its factorization.

81731376 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 424 (or 412 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The square root of 81731376 is about 9040.5406917949. The cubic root of 81731376 is about 433.9732263492.

The spelling of 81731376 in words is "eighty-one million, seven hundred thirty-one thousand, three hundred seventy-six".