81141220 has 12 divisors (see below), whose sum is σ = 170396604. Its totient is φ = 32456480.

The previous prime is 81141157. The next prime is 81141233. The reversal of 81141220 is 2214118.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 24681024 + 56460196 = 4968^2 + 7514^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2028511 + ... + 2028550.

It is an arithmetic number, because the mean of its divisors is an integer number (14199717).

Almost surely, 2^81141220 is an apocalyptic number.

It is an amenable number.

81141220 is an abundant number, since it is smaller than the sum of its proper divisors (89255384).

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

81141220 is a wasteful number, since it uses less digits than its factorization.

81141220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4057070 (or 4057068 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 81141220 is about 9007.8421389365. The cubic root of 81141220 is about 432.9261750835.

Adding to 81141220 its reverse (2214118), we get a palindrome (83355338).

The spelling of 81141220 in words is "eighty-one million, one hundred forty-one thousand, two hundred twenty".