81266616 has 24 divisors (see below), whose sum is σ = 220097280. Its totient is φ = 27088848.

The previous prime is 81266611. The next prime is 81266617. The reversal of 81266616 is 61666218.

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81266611) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 564280 + ... + 564423.

It is an arithmetic number, because the mean of its divisors is an integer number (9170720).

Almost surely, 2^81266616 is an apocalyptic number.

It is an amenable number.

81266616 is an abundant number, since it is smaller than the sum of its proper divisors (138830664).

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

81266616 is a wasteful number, since it uses less digits than its factorization.

81266616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1128715 (or 1128708 counting only the distinct ones).

The product of its digits is 20736, while the sum is 36.

The square root of 81266616 is about 9014.7998313884. The cubic root of 81266616 is about 433.1490756405.

The spelling of 81266616 in words is "eighty-one million, two hundred sixty-six thousand, six hundred sixteen".