81866148 has 96 divisors (see below), whose sum is σ = 239151360. Its totient is φ = 21219840.

The previous prime is 81866143. The next prime is 81866153. The reversal of 81866148 is 84166818.

It is an interprime number because it is at equal distance from previous prime (81866143) and next prime (81866153).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (81866143) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 65998 + ... + 67226.

It is an arithmetic number, because the mean of its divisors is an integer number (2491160).

Almost surely, 2^81866148 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81866148, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119575680).

81866148 is an abundant number, since it is smaller than the sum of its proper divisors (157285212).

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

81866148 is a wasteful number, since it uses less digits than its factorization.

81866148 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1317 (or 1315 counting only the distinct ones).

The product of its digits is 73728, while the sum is 42.

The square root of 81866148 is about 9047.9913793062. The cubic root of 81866148 is about 434.2116305952.

It can be divided in two parts, 818 and 66148, that added together give a palindrome (66966).

The spelling of 81866148 in words is "eighty-one million, eight hundred sixty-six thousand, one hundred forty-eight".