81432180 has 36 divisors (see below), whose sum is σ = 247011492. Its totient is φ = 21715200.

The previous prime is 81432163. The next prime is 81432187. The reversal of 81432180 is 8123418.

It can be written as a sum of positive squares in 2 ways, for example, as 16597476 + 64834704 = 4074^2 + 8052^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81432187) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 226021 + ... + 226380.

Almost surely, 2^81432180 is an apocalyptic number.

It is an amenable number.

81432180 is an abundant number, since it is smaller than the sum of its proper divisors (165579312).

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

81432180 is a wasteful number, since it uses less digits than its factorization.

81432180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 452416 (or 452411 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 81432180 is about 9023.9780584840. The cubic root of 81432180 is about 433.4430267994.

Adding to 81432180 its reverse (8123418), we get a palindrome (89555598).

The spelling of 81432180 in words is "eighty-one million, four hundred thirty-two thousand, one hundred eighty".