81222280 has 32 divisors (see below), whose sum is σ = 183484440. Its totient is φ = 32358400.

The previous prime is 81222259. The next prime is 81222299. The reversal of 81222280 is 8222218.

It can be written as a sum of positive squares in 4 ways, for example, as 81108036 + 114244 = 9006^2 + 338^2 .

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 7 ways as a sum of consecutive naturals, for example, 6330 + ... + 14230.

Almost surely, 2^81222280 is an apocalyptic number.

It is an amenable number.

81222280 is an abundant number, since it is smaller than the sum of its proper divisors (102262160).

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

81222280 is a wasteful number, since it uses less digits than its factorization.

81222280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8169 (or 8165 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 25.

The square root of 81222280 is about 9012.3404285457. The cubic root of 81222280 is about 433.0702913797.

Adding to 81222280 its reverse (8222218), we get a palindrome (89444498).

The spelling of 81222280 in words is "eighty-one million, two hundred twenty-two thousand, two hundred eighty".