81035870220 has 144 divisors (see below), whose sum is σ = 247211546400. Its totient is φ = 21486624768.

The previous prime is 81035870191. The next prime is 81035870221. The reversal of 81035870220 is 2207853018.

81035870220 is a `hidden beast` number, since 8 + 10 + 358 + 70 + 220 = 666.

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 (81035870221) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 25618359 + ... + 25621521.

It is an arithmetic number, because the mean of its divisors is an integer number (1716746850).

Almost surely, 2^81035870220 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81035870220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (123605773200).

81035870220 is an abundant number, since it is smaller than the sum of its proper divisors (166175676180).

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

81035870220 is a wasteful number, since it uses less digits than its factorization.

81035870220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3944 (or 3939 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The spelling of 81035870220 in words is "eighty-one billion, thirty-five million, eight hundred seventy thousand, two hundred twenty".