81100305 has 64 divisors (see below), whose sum is σ = 169424640. Its totient is φ = 36288000.

The previous prime is 81100289. The next prime is 81100307. The reversal of 81100305 is 50300118.

It is a happy number.

It is not a de Polignac number, because 81100305 - 2⁴ = 81100289 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81100307) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 17205 + ... + 21405.

It is an arithmetic number, because the mean of its divisors is an integer number (2647260).

Almost surely, 2^81100305 is an apocalyptic number.

It is an amenable number.

81100305 is an abundant number, since it is smaller than the sum of its proper divisors (88324335).

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

81100305 is a wasteful number, since it uses less digits than its factorization.

81100305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4239 (or 4233 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 81100305 is about 9005.5707759142. The cubic root of 81100305 is about 432.8533959932.

The spelling of 81100305 in words is "eighty-one million, one hundred thousand, three hundred five".