81009792 has 48 divisors (see below), whose sum is σ = 233117430. Its totient is φ = 27002880.

The previous prime is 81009763. The next prime is 81009821. The reversal of 81009792 is 29790018.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81009763) and next prime (81009821).

It can be written as a sum of positive squares in only one way, i.e., 48108096 + 32901696 = 6936^2 + 5736^2 .

It is a tau number, because it is divible by the number of its divisors (48).

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

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 34009 + ... + 36312.

Almost surely, 2^81009792 is an apocalyptic number.

It is an amenable number.

81009792 is an abundant number, since it is smaller than the sum of its proper divisors (152107638).

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

81009792 is a wasteful number, since it uses less digits than its factorization.

81009792 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70341 (or 70326 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 36.

The square root of 81009792 is about 9000.5439835601. The cubic root of 81009792 is about 432.6923055845.

The spelling of 81009792 in words is "eighty-one million, nine thousand, seven hundred ninety-two".