81640062220 has 24 divisors (see below), whose sum is σ = 180467506800. Its totient is φ = 30937286592.

The previous prime is 81640062191. The next prime is 81640062223. The reversal of 81640062220 is 2226004618.

It is not an unprimeable number, because it can be changed into a prime (81640062223) by changing a digit.

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, 107420755 + ... + 107421514.

It is an arithmetic number, because the mean of its divisors is an integer number (7519479450).

Almost surely, 2^81640062220 is an apocalyptic number.

It is an amenable number.

81640062220 is an abundant number, since it is smaller than the sum of its proper divisors (98827444580).

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

81640062220 is a wasteful number, since it uses less digits than its factorization.

81640062220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214842297 (or 214842295 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 31.

Adding to 81640062220 its reverse (2226004618), we get a palindrome (83866066838).

The spelling of 81640062220 in words is "eighty-one billion, six hundred forty million, sixty-two thousand, two hundred twenty".