81758389 has 12 divisors (see below), whose sum is σ = 87741828. Its totient is φ = 76160000.

The previous prime is 81758381. The next prime is 81758401. The reversal of 81758389 is 98385718.

It can be written as a sum of positive squares in 6 ways, for example, as 25583364 + 56175025 = 5058^2 + 7495^2 .

It is not a de Polignac number, because 81758389 - 2³ = 81758381 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81758381) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27789 + ... + 30589.

It is an arithmetic number, because the mean of its divisors is an integer number (7311819).

Almost surely, 2^81758389 is an apocalyptic number.

It is an amenable number.

81758389 is a deficient number, since it is larger than the sum of its proper divisors (5983439).

81758389 is a wasteful number, since it uses less digits than its factorization.

81758389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2936 (or 2919 counting only the distinct ones).

The product of its digits is 483840, while the sum is 49.

The square root of 81758389 is about 9042.0345608718. The cubic root of 81758389 is about 434.0210318476.

The spelling of 81758389 in words is "eighty-one million, seven hundred fifty-eight thousand, three hundred eighty-nine".