81368220 has 48 divisors (see below), whose sum is σ = 230590080. Its totient is φ = 21435456.

The previous prime is 81368213. The next prime is 81368269. The reversal of 81368220 is 2286318.

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

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3190 + ... + 13149.

It is an arithmetic number, because the mean of its divisors is an integer number (4803960).

Almost surely, 2^81368220 is an apocalyptic number.

It is an amenable number.

81368220 is an abundant number, since it is smaller than the sum of its proper divisors (149221860).

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

81368220 is a wasteful number, since it uses less digits than its factorization.

81368220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16434 (or 16432 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 81368220 is about 9020.4334707374. The cubic root of 81368220 is about 433.3295160742.

The spelling of 81368220 in words is "eighty-one million, three hundred sixty-eight thousand, two hundred twenty".