81618264 has 96 divisors (see below), whose sum is σ = 272082720. Its totient is φ = 21523968.

The previous prime is 81618259. The next prime is 81618293. The reversal of 81618264 is 46281618.

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 an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 324 + ... + 12780.

It is an arithmetic number, because the mean of its divisors is an integer number (2834195).

Almost surely, 2^81618264 is an apocalyptic number.

81618264 is a gapful number since it is divisible by the number (84) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81618264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136041360).

81618264 is an abundant number, since it is smaller than the sum of its proper divisors (190464456).

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

81618264 is a wasteful number, since it uses less digits than its factorization.

81618264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12489 (or 12482 counting only the distinct ones).

The product of its digits is 18432, while the sum is 36.

The square root of 81618264 is about 9034.2827053397. The cubic root of 81618264 is about 433.7729350849.

The spelling of 81618264 in words is "eighty-one million, six hundred eighteen thousand, two hundred sixty-four".