81218300 has 18 divisors (see below), whose sum is σ = 176243928. Its totient is φ = 32487280.

The previous prime is 81218251. The next prime is 81218309. The reversal of 81218300 is 381218.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81218309) 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, 405992 + ... + 406191.

Almost surely, 2^81218300 is an apocalyptic number.

It is an amenable number.

81218300 is an abundant number, since it is smaller than the sum of its proper divisors (95025628).

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

81218300 is a wasteful number, since it uses less digits than its factorization.

81218300 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 812197 (or 812190 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 23.

The square root of 81218300 is about 9012.1196174929. The cubic root of 81218300 is about 433.0632175903.

Adding to 81218300 its reverse (381218), we get a palindrome (81599518).

It can be divided in two parts, 81218 and 300, that added together give a palindrome (81518).

The spelling of 81218300 in words is "eighty-one million, two hundred eighteen thousand, three hundred".