81099804 has 24 divisors (see below), whose sum is σ = 193849488. Its totient is φ = 26373760.

The previous prime is 81099803. The next prime is 81099827. The reversal of 81099804 is 40899018.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81099803) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 81927 + ... + 82910.

It is an arithmetic number, because the mean of its divisors is an integer number (8077062).

Almost surely, 2^81099804 is an apocalyptic number.

It is an amenable number.

81099804 is an abundant number, since it is smaller than the sum of its proper divisors (112749684).

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

81099804 is a wasteful number, since it uses less digits than its factorization.

81099804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164885 (or 164883 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 39.

The square root of 81099804 is about 9005.5429597554. The cubic root of 81099804 is about 432.8525046689.

The spelling of 81099804 in words is "eighty-one million, ninety-nine thousand, eight hundred four".