81342220 has 24 divisors (see below), whose sum is σ = 171309600. Its totient is φ = 32443392.

The previous prime is 81342181. The next prime is 81342253. The reversal of 81342220 is 2224318.

It is a junction number, because it is equal to n+sod(n) for n = 81342191 and 81342200.

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, 1516 + ... + 12844.

It is an arithmetic number, because the mean of its divisors is an integer number (7137900).

Almost surely, 2^81342220 is an apocalyptic number.

It is an amenable number.

81342220 is an abundant number, since it is smaller than the sum of its proper divisors (89967380).

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

81342220 is a wasteful number, since it uses less digits than its factorization.

81342220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11697 (or 11695 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 22.

The square root of 81342220 is about 9018.9921831655. The cubic root of 81342220 is about 433.2833564980.

Adding to 81342220 its reverse (2224318), we get a palindrome (83566538).

The spelling of 81342220 in words is "eighty-one million, three hundred forty-two thousand, two hundred twenty".