81085300 has 18 divisors (see below), whose sum is σ = 175955318. Its totient is φ = 32434080.

The previous prime is 81085289. The next prime is 81085321. The reversal of 81085300 is 358018.

It can be written as a sum of positive squares in 3 ways, for example, as 5116644 + 75968656 = 2262^2 + 8716^2 .

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 405327 + ... + 405526.

Almost surely, 2^81085300 is an apocalyptic number.

It is an amenable number.

81085300 is an abundant number, since it is smaller than the sum of its proper divisors (94870018).

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

81085300 is a wasteful number, since it uses less digits than its factorization.

81085300 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 810867 (or 810860 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 81085300 is about 9004.7376419305. The cubic root of 81085300 is about 432.8266991523.

The spelling of 81085300 in words is "eighty-one million, eighty-five thousand, three hundred".