81630929 has 2 divisors, whose sum is σ = 81630930. Its totient is φ = 81630928.

The previous prime is 81630919. The next prime is 81630953. The reversal of 81630929 is 92903618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 58369600 + 23261329 = 7640^2 + 4823^2 .

It is a cyclic number.

It is not a de Polignac number, because 81630929 - 2²⁴ = 64853713 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81630892 and 81630901.

It is not a weakly prime, because it can be changed into another prime (81630919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40815464 + 40815465.

It is an arithmetic number, because the mean of its divisors is an integer number (40815465).

Almost surely, 2^81630929 is an apocalyptic number.

It is an amenable number.

81630929 is a deficient number, since it is larger than the sum of its proper divisors (1).

81630929 is an equidigital number, since it uses as much as digits as its factorization.

81630929 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 81630929 is about 9034.9836192436. The cubic root of 81630929 is about 433.7953706274.

The spelling of 81630929 in words is "eighty-one million, six hundred thirty thousand, nine hundred twenty-nine".