81630529 has 2 divisors, whose sum is σ = 81630530. Its totient is φ = 81630528.

The previous prime is 81630511. The next prime is 81630539. The reversal of 81630529 is 92503618.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73564929 + 8065600 = 8577^2 + 2840^2 .

It is a cyclic number.

It is not a de Polignac number, because 81630529 - 2⁷ = 81630401 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 81630494 and 81630503.

It is not a weakly prime, because it can be changed into another prime (81630509) 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 as a sum of consecutive naturals, namely, 40815264 + 40815265.

It is an arithmetic number, because the mean of its divisors is an integer number (40815265).

Almost surely, 2^81630529 is an apocalyptic number.

It is an amenable number.

81630529 is a deficient number, since it is larger than the sum of its proper divisors (1).

81630529 is an equidigital number, since it uses as much as digits as its factorization.

81630529 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12960, while the sum is 34.

The square root of 81630529 is about 9034.9614830391. The cubic root of 81630529 is about 433.7946620788.

The spelling of 81630529 in words is "eighty-one million, six hundred thirty thousand, five hundred twenty-nine".