81766636 has 12 divisors (see below), whose sum is σ = 163533328. Its totient is φ = 35042832.

The previous prime is 81766613. The next prime is 81766637. The reversal of 81766636 is 63666718.

81766636 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 81766592 and 81766601.

It is not an unprimeable number, because it can be changed into a prime (81766637) 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, 1460091 + ... + 1460146.

Almost surely, 2^81766636 is an apocalyptic number.

It is an amenable number.

81766636 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

81766636 is a wasteful number, since it uses less digits than its factorization.

81766636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2920248 (or 2920246 counting only the distinct ones).

The product of its digits is 217728, while the sum is 43.

The square root of 81766636 is about 9042.4905861162. The cubic root of 81766636 is about 434.0356246462.

The spelling of 81766636 in words is "eighty-one million, seven hundred sixty-six thousand, six hundred thirty-six".