81528229 has 2 divisors, whose sum is σ = 81528230. Its totient is φ = 81528228.

The previous prime is 81528217. The next prime is 81528241. The reversal of 81528229 is 92282518.

It is a balanced prime because it is at equal distance from previous prime (81528217) and next prime (81528241).

It can be written as a sum of positive squares in only one way, i.e., 60871204 + 20657025 = 7802^2 + 4545^2 .

It is a cyclic number.

It is not a de Polignac number, because 81528229 - 2⁷ = 81528101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81522229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40764114 + 40764115.

It is an arithmetic number, because the mean of its divisors is an integer number (40764115).

Almost surely, 2^81528229 is an apocalyptic number.

It is an amenable number.

81528229 is a deficient number, since it is larger than the sum of its proper divisors (1).

81528229 is an equidigital number, since it uses as much as digits as its factorization.

81528229 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23040, while the sum is 37.

The square root of 81528229 is about 9029.2983669829. The cubic root of 81528229 is about 433.6133747372.

The spelling of 81528229 in words is "eighty-one million, five hundred twenty-eight thousand, two hundred twenty-nine".