81800748 has 36 divisors (see below), whose sum is σ = 207567360. Its totient is φ = 27162336.

The previous prime is 81800743. The next prime is 81800759. The reversal of 81800748 is 84700818.

It is a tau number, because it is divible by the number of its divisors (36).

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

It is not an unprimeable number, because it can be changed into a prime (81800743) 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 11 ways as a sum of consecutive naturals, for example, 5461 + ... + 13907.

It is an arithmetic number, because the mean of its divisors is an integer number (5765760).

Almost surely, 2^81800748 is an apocalyptic number.

It is an amenable number.

81800748 is an abundant number, since it is smaller than the sum of its proper divisors (125766612).

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

81800748 is a wasteful number, since it uses less digits than its factorization.

81800748 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8726 (or 8721 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 81800748 is about 9044.3765954321. The cubic root of 81800748 is about 434.0959743010.

The spelling of 81800748 in words is "eighty-one million, eight hundred thousand, seven hundred forty-eight".