81499392 has 144 divisors (see below), whose sum is σ = 259833280. Its totient is φ = 25049088.

The previous prime is 81499387. The next prime is 81499393. The reversal of 81499392 is 29399418.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81499393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 89403 + ... + 90309.

Almost surely, 2^81499392 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 81499392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129916640).

81499392 is an abundant number, since it is smaller than the sum of its proper divisors (178333888).

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

81499392 is a wasteful number, since it uses less digits than its factorization.

81499392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 945 (or 925 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 81499392 is about 9027.7013685655. The cubic root of 81499392 is about 433.5622448665.

The spelling of 81499392 in words is "eighty-one million, four hundred ninety-nine thousand, three hundred ninety-two".