81602173361 has 2 divisors, whose sum is σ = 81602173362. Its totient is φ = 81602173360.

The previous prime is 81602173349. The next prime is 81602173369. The reversal of 81602173361 is 16337120618.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73766560000 + 7835613361 = 271600^2 + 88519^2 .

It is a cyclic number.

It is not a de Polignac number, because 81602173361 - 2¹⁸ = 81601911217 is a prime.

It is not a weakly prime, because it can be changed into another prime (81602173369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40801086680 + 40801086681.

It is an arithmetic number, because the mean of its divisors is an integer number (40801086681).

Almost surely, 2^81602173361 is an apocalyptic number.

It is an amenable number.

81602173361 is a deficient number, since it is larger than the sum of its proper divisors (1).

81602173361 is an equidigital number, since it uses as much as digits as its factorization.

81602173361 is an evil number, because the sum of its binary digits is even.

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

Adding to 81602173361 its reverse (16337120618), we get a palindrome (97939293979).

The spelling of 81602173361 in words is "eighty-one billion, six hundred two million, one hundred seventy-three thousand, three hundred sixty-one".