81612213 has 8 divisors (see below), whose sum is σ = 109054176. Its totient is φ = 54289200.

The previous prime is 81612203. The next prime is 81612227. The reversal of 81612213 is 31221618.

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

It is not a de Polignac number, because 81612213 - 2¹⁶ = 81546677 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81612203) 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, 28123 + ... + 30888.

It is an arithmetic number, because the mean of its divisors is an integer number (13631772).

Almost surely, 2^81612213 is an apocalyptic number.

It is an amenable number.

81612213 is a deficient number, since it is larger than the sum of its proper divisors (27441963).

81612213 is a wasteful number, since it uses less digits than its factorization.

81612213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59475.

The product of its digits is 576, while the sum is 24.

The square root of 81612213 is about 9033.9478081291. The cubic root of 81612213 is about 433.7622151604.

The spelling of 81612213 in words is "eighty-one million, six hundred twelve thousand, two hundred thirteen".