81767538 has 24 divisors (see below), whose sum is σ = 178088508. Its totient is φ = 27113472.

The previous prime is 81767531. The next prime is 81767551. The reversal of 81767538 is 83576718.

It can be written as a sum of positive squares in 2 ways, for example, as 77739489 + 4028049 = 8817^2 + 2007^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81767493 and 81767502.

It is not an unprimeable number, because it can be changed into a prime (81767531) 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, 8295 + ... + 15242.

Almost surely, 2^81767538 is an apocalyptic number.

81767538 is an abundant number, since it is smaller than the sum of its proper divisors (96320970).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81767538 is a wasteful number, since it uses less digits than its factorization.

81767538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23738 (or 23735 counting only the distinct ones).

The product of its digits is 282240, while the sum is 45.

The square root of 81767538 is about 9042.5404616181. The cubic root of 81767538 is about 434.0372206463.

The spelling of 81767538 in words is "eighty-one million, seven hundred sixty-seven thousand, five hundred thirty-eight".