81630229 has 4 divisors (see below), whose sum is σ = 83170476. Its totient is φ = 80089984.

The previous prime is 81630181. The next prime is 81630247. The reversal of 81630229 is 92203618.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20007729 + 61622500 = 4473^2 + 7850^2 .

It is a cyclic number.

It is not a de Polignac number, because 81630229 - 2¹⁷ = 81499157 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 81630229.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81630529) 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 3 ways as a sum of consecutive naturals, for example, 770044 + ... + 770149.

It is an arithmetic number, because the mean of its divisors is an integer number (20792619).

Almost surely, 2^81630229 is an apocalyptic number.

It is an amenable number.

81630229 is a deficient number, since it is larger than the sum of its proper divisors (1540247).

81630229 is a wasteful number, since it uses less digits than its factorization.

81630229 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1540246.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 81630229 is about 9034.9448808501. The cubic root of 81630229 is about 433.7941306659.

The spelling of 81630229 in words is "eighty-one million, six hundred thirty thousand, two hundred twenty-nine".