81813150 has 72 divisors (see below), whose sum is σ = 220927824. Its totient is φ = 21705600.

The previous prime is 81813143. The next prime is 81813157. The reversal of 81813150 is 5131818.

It is an interprime number because it is at equal distance from previous prime (81813143) and next prime (81813157).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81813157) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 126127 + ... + 126773.

It is an arithmetic number, because the mean of its divisors is an integer number (3068442).

Almost surely, 2^81813150 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81813150, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110463912).

81813150 is an abundant number, since it is smaller than the sum of its proper divisors (139114674).

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

81813150 is a wasteful number, since it uses less digits than its factorization.

81813150 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 946 (or 938 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 27.

The square root of 81813150 is about 9045.0621888409. The cubic root of 81813150 is about 434.1179112895.

Adding to 81813150 its reverse (5131818), we get a palindrome (86944968).

The spelling of 81813150 in words is "eighty-one million, eight hundred thirteen thousand, one hundred fifty".