81818190 has 24 divisors (see below), whose sum is σ = 212727528. Its totient is φ = 21818160.

The previous prime is 81818179. The next prime is 81818197. The reversal of 81818190 is 9181818.

It is a super-2 number, since 2×81818190² = 13388432429752200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81818197) 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, 454456 + ... + 454635.

It is an arithmetic number, because the mean of its divisors is an integer number (8863647).

Almost surely, 2^81818190 is an apocalyptic number.

81818190 is an abundant number, since it is smaller than the sum of its proper divisors (130909338).

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

81818190 is a wasteful number, since it uses less digits than its factorization.

81818190 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 909104 (or 909101 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 36.

The square root of 81818190 is about 9045.3407895999. The cubic root of 81818190 is about 434.1268255425.

The spelling of 81818190 in words is "eighty-one million, eight hundred eighteen thousand, one hundred ninety".