81794989 has 2 divisors, whose sum is σ = 81794990. Its totient is φ = 81794988.

The previous prime is 81794929. The next prime is 81795001. The reversal of 81794989 is 98949718.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73239364 + 8555625 = 8558^2 + 2925^2 .

It is a cyclic number.

It is not a de Polignac number, because 81794989 - 2¹¹ = 81792941 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81794929) 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, 40897494 + 40897495.

It is an arithmetic number, because the mean of its divisors is an integer number (40897495).

Almost surely, 2^81794989 is an apocalyptic number.

It is an amenable number.

81794989 is a deficient number, since it is larger than the sum of its proper divisors (1).

81794989 is an equidigital number, since it uses as much as digits as its factorization.

81794989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1306368, while the sum is 55.

The square root of 81794989 is about 9044.0582152041. The cubic root of 81794989 is about 434.0857868742.

The spelling of 81794989 in words is "eighty-one million, seven hundred ninety-four thousand, nine hundred eighty-nine".