81502189 has 2 divisors, whose sum is σ = 81502190. Its totient is φ = 81502188.

The previous prime is 81502171. The next prime is 81502247. The reversal of 81502189 is 98120518.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81090025 + 412164 = 9005^2 + 642^2 .

It is a cyclic number.

It is not a de Polignac number, because 81502189 - 2¹⁷ = 81371117 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81502139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40751094 + 40751095.

It is an arithmetic number, because the mean of its divisors is an integer number (40751095).

Almost surely, 2^81502189 is an apocalyptic number.

It is an amenable number.

81502189 is a deficient number, since it is larger than the sum of its proper divisors (1).

81502189 is an equidigital number, since it uses as much as digits as its factorization.

81502189 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5760, while the sum is 34.

The square root of 81502189 is about 9027.8562793168. The cubic root of 81502189 is about 433.5672046569.

The spelling of 81502189 in words is "eighty-one million, five hundred two thousand, one hundred eighty-nine".