81324220 has 24 divisors (see below), whose sum is σ = 171082800. Its totient is φ = 32472192.

The previous prime is 81324193. The next prime is 81324233. The reversal of 81324220 is 2242318.

It is a super-2 number, since 2×81324220² = 13227257517216800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 81324191 and 81324200.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9096 + ... + 15664.

It is an arithmetic number, because the mean of its divisors is an integer number (7128450).

Almost surely, 2^81324220 is an apocalyptic number.

It is an amenable number.

81324220 is an abundant number, since it is smaller than the sum of its proper divisors (89758580).

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

81324220 is a wasteful number, since it uses less digits than its factorization.

81324220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7197 (or 7195 counting only the distinct ones).

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

The square root of 81324220 is about 9017.9942337529. The cubic root of 81324220 is about 433.2513941060.

Adding to 81324220 its reverse (2242318), we get a palindrome (83566538).

The spelling of 81324220 in words is "eighty-one million, three hundred twenty-four thousand, two hundred twenty".