81354322221 has 16 divisors (see below), whose sum is σ = 109348373760. Its totient is φ = 53799992640.

The previous prime is 81354322219. The next prime is 81354322229. The reversal of 81354322221 is 12222345318.

It is not a de Polignac number, because 81354322221 - 2¹ = 81354322219 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81354322229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32310 + ... + 404663.

It is an arithmetic number, because the mean of its divisors is an integer number (6834273360).

Almost surely, 2^81354322221 is an apocalyptic number.

It is an amenable number.

81354322221 is a deficient number, since it is larger than the sum of its proper divisors (27994051539).

81354322221 is a wasteful number, since it uses less digits than its factorization.

81354322221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 437476.

The product of its digits is 23040, while the sum is 33.

Adding to 81354322221 its reverse (12222345318), we get a palindrome (93576667539).

The spelling of 81354322221 in words is "eighty-one billion, three hundred fifty-four million, three hundred twenty-two thousand, two hundred twenty-one".