81896869 has 2 divisors, whose sum is σ = 81896870. Its totient is φ = 81896868.

The previous prime is 81896827. The next prime is 81896909. The reversal of 81896869 is 96869818.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46648900 + 35247969 = 6830^2 + 5937^2 .

It is a cyclic number.

It is not a de Polignac number, because 81896869 - 2⁷ = 81896741 is a prime.

It is a super-2 number, since 2×81896869² = 13414194304006322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81896069) 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, 40948434 + 40948435.

It is an arithmetic number, because the mean of its divisors is an integer number (40948435).

Almost surely, 2^81896869 is an apocalyptic number.

It is an amenable number.

81896869 is a deficient number, since it is larger than the sum of its proper divisors (1).

81896869 is an equidigital number, since it uses as much as digits as its factorization.

81896869 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1492992, while the sum is 55.

The square root of 81896869 is about 9049.6888896801. The cubic root of 81896869 is about 434.2659377279.

The spelling of 81896869 in words is "eighty-one million, eight hundred ninety-six thousand, eight hundred sixty-nine".