81783800 has 48 divisors (see below), whose sum is σ = 217314960. Its totient is φ = 28039680.

The previous prime is 81783773. The next prime is 81783803. The reversal of 81783800 is 838718.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81783803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27809 + ... + 30608.

It is an arithmetic number, because the mean of its divisors is an integer number (4527395).

Almost surely, 2^81783800 is an apocalyptic number.

It is an amenable number.

81783800 is an abundant number, since it is smaller than the sum of its proper divisors (135531160).

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

81783800 is a wasteful number, since it uses less digits than its factorization.

81783800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58440 (or 58431 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 35.

The square root of 81783800 is about 9043.4396111214. The cubic root of 81783800 is about 434.0659926406.

The spelling of 81783800 in words is "eighty-one million, seven hundred eighty-three thousand, eight hundred".