81501681169 has 2 divisors, whose sum is σ = 81501681170. Its totient is φ = 81501681168.

The previous prime is 81501681139. The next prime is 81501681199. The reversal of 81501681169 is 96118610518.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (81501681139) and next prime (81501681199).

It can be written as a sum of positive squares in only one way, i.e., 70496622144 + 11005059025 = 265512^2 + 104905^2 .

It is a cyclic number.

It is not a de Polignac number, because 81501681169 - 2⁵ = 81501681137 is a prime.

It is a super-2 number, since 2×81501681169² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81501681139) 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, 40750840584 + 40750840585.

It is an arithmetic number, because the mean of its divisors is an integer number (40750840585).

Almost surely, 2^81501681169 is an apocalyptic number.

It is an amenable number.

81501681169 is a deficient number, since it is larger than the sum of its proper divisors (1).

81501681169 is an equidigital number, since it uses as much as digits as its factorization.

81501681169 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 103680, while the sum is 46.

The spelling of 81501681169 in words is "eighty-one billion, five hundred one million, six hundred eighty-one thousand, one hundred sixty-nine".