81643097 has 2 divisors, whose sum is σ = 81643098. Its totient is φ = 81643096.

The previous prime is 81643049. The next prime is 81643099. The reversal of 81643097 is 79034618.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73685056 + 7958041 = 8584^2 + 2821^2 .

It is a cyclic number.

It is not a de Polignac number, because 81643097 - 2¹⁸ = 81380953 is a prime.

Together with 81643099, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81643097.

It is not a weakly prime, because it can be changed into another prime (81643099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40821548 + 40821549.

It is an arithmetic number, because the mean of its divisors is an integer number (40821549).

Almost surely, 2^81643097 is an apocalyptic number.

It is an amenable number.

81643097 is a deficient number, since it is larger than the sum of its proper divisors (1).

81643097 is an equidigital number, since it uses as much as digits as its factorization.

81643097 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36288, while the sum is 38.

The square root of 81643097 is about 9035.6569766675. The cubic root of 81643097 is about 433.8169235685.

The spelling of 81643097 in words is "eighty-one million, six hundred forty-three thousand, ninety-seven".