81312229 has 8 divisors (see below), whose sum is σ = 87207840. Its totient is φ = 75578256.

The previous prime is 81312223. The next prime is 81312233. The reversal of 81312229 is 92221318.

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 81312229 - 2³ = 81312221 is a prime.

It is a super-2 number, since 2×81312229² = 13223357169896882, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81312197 and 81312206.

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, 39367 + ... + 41380.

It is an arithmetic number, because the mean of its divisors is an integer number (10900980).

Almost surely, 2^81312229 is an apocalyptic number.

It is an amenable number.

81312229 is a deficient number, since it is larger than the sum of its proper divisors (5895611).

81312229 is a wasteful number, since it uses less digits than its factorization.

81312229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80819.

The product of its digits is 1728, while the sum is 28.

The square root of 81312229 is about 9017.3293718262. The cubic root of 81312229 is about 433.2300992084.

The spelling of 81312229 in words is "eighty-one million, three hundred twelve thousand, two hundred twenty-nine".