81368646 has 16 divisors (see below), whose sum is σ = 164020224. Its totient is φ = 26909064.

The previous prime is 81368593. The next prime is 81368653. The reversal of 81368646 is 64686318.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 81368598 and 81368607.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52630 + ... + 54153.

It is an arithmetic number, because the mean of its divisors is an integer number (10251264).

Almost surely, 2^81368646 is an apocalyptic number.

81368646 is an abundant number, since it is smaller than the sum of its proper divisors (82651578).

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

81368646 is a wasteful number, since it uses less digits than its factorization.

81368646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106915.

The product of its digits is 165888, while the sum is 42.

The square root of 81368646 is about 9020.4570837624. The cubic root of 81368646 is about 433.3302722992.

The spelling of 81368646 in words is "eighty-one million, three hundred sixty-eight thousand, six hundred forty-six".