81266656 has 12 divisors (see below), whose sum is σ = 159993792. Its totient is φ = 40633312.

The previous prime is 81266623. The next prime is 81266657. The reversal of 81266656 is 65666218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81266657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1269760 + ... + 1269823.

It is an arithmetic number, because the mean of its divisors is an integer number (13332816).

Almost surely, 2^81266656 is an apocalyptic number.

It is an amenable number.

81266656 is a deficient number, since it is larger than the sum of its proper divisors (78727136).

81266656 is a wasteful number, since it uses less digits than its factorization.

81266656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2539593 (or 2539585 counting only the distinct ones).

The product of its digits is 103680, while the sum is 40.

The square root of 81266656 is about 9014.8020499621. The cubic root of 81266656 is about 433.1491467069.

The spelling of 81266656 in words is "eighty-one million, two hundred sixty-six thousand, six hundred fifty-six".