81738941236 has 12 divisors (see below), whose sum is σ = 143299961028. Its totient is φ = 40796095232.

The previous prime is 81738941227. The next prime is 81738941237. The reversal of 81738941236 is 63214983718.

It can be written as a sum of positive squares in 2 ways, for example, as 6282147600 + 75456793636 = 79260^2 + 274694^2 .

It is a super-2 number, since 2×81738941236² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81738941237) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18341341 + ... + 18345796.

It is an arithmetic number, because the mean of its divisors is an integer number (11941663419).

Almost surely, 2^81738941236 is an apocalyptic number.

It is an amenable number.

81738941236 is a deficient number, since it is larger than the sum of its proper divisors (61561019792).

81738941236 is a wasteful number, since it uses less digits than its factorization.

81738941236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36687698 (or 36687696 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 52.

The spelling of 81738941236 in words is "eighty-one billion, seven hundred thirty-eight million, nine hundred forty-one thousand, two hundred thirty-six".