81764869 has 2 divisors, whose sum is σ = 81764870. Its totient is φ = 81764868.

The previous prime is 81764791. The next prime is 81764899. The reversal of 81764869 is 96846718.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64995844 + 16769025 = 8062^2 + 4095^2 .

It is a cyclic number.

It is not a de Polignac number, because 81764869 - 2⁷ = 81764741 is a prime.

It is a super-2 number, since 2×81764869² = 13370987605174322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81764899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40882434 + 40882435.

It is an arithmetic number, because the mean of its divisors is an integer number (40882435).

Almost surely, 2^81764869 is an apocalyptic number.

It is an amenable number.

81764869 is a deficient number, since it is larger than the sum of its proper divisors (1).

81764869 is an equidigital number, since it uses as much as digits as its factorization.

81764869 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 580608, while the sum is 49.

The square root of 81764869 is about 9042.3928802060. The cubic root of 81764869 is about 434.0324980797.

The spelling of 81764869 in words is "eighty-one million, seven hundred sixty-four thousand, eight hundred sixty-nine".