81228180 has 96 divisors (see below), whose sum is σ = 258951168. Its totient is φ = 18832000.

The previous prime is 81228179. The next prime is 81228197. The reversal of 81228180 is 8182218.

It is a super-2 number, since 2×81228180² = 13196034452224800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12505 + ... + 17855.

It is an arithmetic number, because the mean of its divisors is an integer number (2697408).

Almost surely, 2^81228180 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 81228180, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129475584).

81228180 is an abundant number, since it is smaller than the sum of its proper divisors (177722988).

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

81228180 is a wasteful number, since it uses less digits than its factorization.

81228180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5397 (or 5395 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 30.

The square root of 81228180 is about 9012.6677515595. The cubic root of 81228180 is about 433.0807772252.

The spelling of 81228180 in words is "eighty-one million, two hundred twenty-eight thousand, one hundred eighty".