81713220 has 48 divisors (see below), whose sum is σ = 242258688. Its totient is φ = 20508160.

The previous prime is 81713189. The next prime is 81713249. The reversal of 81713220 is 2231718.

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, 39036 + ... + 41075.

It is an arithmetic number, because the mean of its divisors is an integer number (5047056).

Almost surely, 2^81713220 is an apocalyptic number.

It is an amenable number.

81713220 is an abundant number, since it is smaller than the sum of its proper divisors (160545468).

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

81713220 is a wasteful number, since it uses less digits than its factorization.

81713220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80140 (or 80138 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 81713220 is about 9039.5364925421. The cubic root of 81713220 is about 433.9410893586.

Adding to 81713220 its reverse (2231718), we get a palindrome (83944938).

The spelling of 81713220 in words is "eighty-one million, seven hundred thirteen thousand, two hundred twenty".