81529313 has 2 divisors, whose sum is σ = 81529314. Its totient is φ = 81529312.

The previous prime is 81529303. The next prime is 81529337. The reversal of 81529313 is 31392518.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 73136704 + 8392609 = 8552^2 + 2897^2 .

It is a cyclic number.

It is not a de Polignac number, because 81529313 - 2¹⁸ = 81267169 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81529313.

It is not a weakly prime, because it can be changed into another prime (81529303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40764656 + 40764657.

It is an arithmetic number, because the mean of its divisors is an integer number (40764657).

Almost surely, 2^81529313 is an apocalyptic number.

It is an amenable number.

81529313 is a deficient number, since it is larger than the sum of its proper divisors (1).

81529313 is an equidigital number, since it uses as much as digits as its factorization.

81529313 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6480, while the sum is 32.

The square root of 81529313 is about 9029.3583935959. The cubic root of 81529313 is about 433.6152965044.

The spelling of 81529313 in words is "eighty-one million, five hundred twenty-nine thousand, three hundred thirteen".