81266660 has 24 divisors (see below), whose sum is σ = 171102456. Its totient is φ = 32422400.

The previous prime is 81266657. The next prime is 81266677. The reversal of 81266660 is 6666218.

It can be written as a sum of positive squares in 4 ways, for example, as 43983424 + 37283236 = 6632^2 + 6106^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81266660.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2954 + ... + 13086.

It is an arithmetic number, because the mean of its divisors is an integer number (7129269).

Almost surely, 2^81266660 is an apocalyptic number.

It is an amenable number.

81266660 is an abundant number, since it is smaller than the sum of its proper divisors (89835796).

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

81266660 is a wasteful number, since it uses less digits than its factorization.

81266660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10543 (or 10541 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 35.

The square root of 81266660 is about 9014.8022718194. The cubic root of 81266660 is about 433.1491538135.

The spelling of 81266660 in words is "eighty-one million, two hundred sixty-six thousand, six hundred sixty".