81366426 has 24 divisors (see below), whose sum is σ = 178779744. Its totient is φ = 26739720.

The previous prime is 81366421. The next prime is 81366443. The reversal of 81366426 is 62466318.

81366426 is a `hidden beast` number, since 8 + 1 + 3 + 6 + 642 + 6 = 666.

It is not an unprimeable number, because it can be changed into a prime (81366421) 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, 30556 + ... + 33111.

It is an arithmetic number, because the mean of its divisors is an integer number (7449156).

Almost surely, 2^81366426 is an apocalyptic number.

81366426 is an abundant number, since it is smaller than the sum of its proper divisors (97413318).

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

81366426 is a wasteful number, since it uses less digits than its factorization.

81366426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63746 (or 63743 counting only the distinct ones).

The product of its digits is 41472, while the sum is 36.

The square root of 81366426 is about 9020.3340292918. The cubic root of 81366426 is about 433.3263313793.

The spelling of 81366426 in words is "eighty-one million, three hundred sixty-six thousand, four hundred twenty-six".