81435769 has 2 divisors, whose sum is σ = 81435770. Its totient is φ = 81435768.

The previous prime is 81435751. The next prime is 81435803. The reversal of 81435769 is 96753418.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81090025 + 345744 = 9005^2 + 588^2 .

It is a cyclic number.

It is not a de Polignac number, because 81435769 - 2⁵ = 81435737 is a prime.

It is a super-2 number, since 2×81435769² = 13263568945242722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (81435749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40717884 + 40717885.

It is an arithmetic number, because the mean of its divisors is an integer number (40717885).

Almost surely, 2^81435769 is an apocalyptic number.

It is an amenable number.

81435769 is a deficient number, since it is larger than the sum of its proper divisors (1).

81435769 is an equidigital number, since it uses as much as digits as its factorization.

81435769 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 181440, while the sum is 43.

The square root of 81435769 is about 9024.1769153757. The cubic root of 81435769 is about 433.4493944874.

The spelling of 81435769 in words is "eighty-one million, four hundred thirty-five thousand, seven hundred sixty-nine".