81431296 has 54 divisors (see below), whose sum is σ = 168464436. Its totient is φ = 39283200.

The previous prime is 81431291. The next prime is 81431299. The reversal of 81431296 is 69213418.

It is not an unprimeable number, because it can be changed into a prime (81431291) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 245851 + ... + 246181.

Almost surely, 2^81431296 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 81431296, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84232218).

81431296 is an abundant number, since it is smaller than the sum of its proper divisors (87033140).

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

81431296 is an equidigital number, since it uses as much as digits as its factorization.

81431296 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409 (or 364 counting only the distinct ones).

The product of its digits is 10368, while the sum is 34.

The square root of 81431296 is about 9023.9290777355. The cubic root of 81431296 is about 433.4414583571.

The spelling of 81431296 in words is "eighty-one million, four hundred thirty-one thousand, two hundred ninety-six".