81965759 has 2 divisors, whose sum is σ = 81965760. Its totient is φ = 81965758.

The previous prime is 81965743. The next prime is 81965777. The reversal of 81965759 is 95756918.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81965759 - 2⁴ = 81965743 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81965159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40982879 + 40982880.

It is an arithmetic number, because the mean of its divisors is an integer number (40982880).

Almost surely, 2^81965759 is an apocalyptic number.

81965759 is a deficient number, since it is larger than the sum of its proper divisors (1).

81965759 is an equidigital number, since it uses as much as digits as its factorization.

81965759 is an evil number, because the sum of its binary digits is even.

The product of its digits is 680400, while the sum is 50.

The square root of 81965759 is about 9053.4942977836. The cubic root of 81965759 is about 434.3876688609.

It can be divided in two parts, 81965 and 759, that multiplied together give a triangular number (62211435 = T₁₁₁₅₄).

The spelling of 81965759 in words is "eighty-one million, nine hundred sixty-five thousand, seven hundred fifty-nine".