81342221 has 8 divisors (see below), whose sum is σ = 83692224. Its totient is φ = 79025760.

The previous prime is 81342181. The next prime is 81342253. The reversal of 81342221 is 12224318.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81342221 - 2²⁶ = 14233357 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81312221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3425 + ... + 13206.

It is an arithmetic number, because the mean of its divisors is an integer number (10461528).

Almost surely, 2^81342221 is an apocalyptic number.

It is an amenable number.

81342221 is a deficient number, since it is larger than the sum of its proper divisors (2350003).

81342221 is a wasteful number, since it uses less digits than its factorization.

81342221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16771.

The product of its digits is 768, while the sum is 23.

The square root of 81342221 is about 9018.9922386040. The cubic root of 81342221 is about 433.2833582736.

Adding to 81342221 its reverse (12224318), we get a palindrome (93566539).

It can be divided in two parts, 813 and 42221, that added together give a palindrome (43034).

The spelling of 81342221 in words is "eighty-one million, three hundred forty-two thousand, two hundred twenty-one".