12181890 has 48 divisors (see below), whose sum is σ = 34013952. Its totient is φ = 2784096.

The previous prime is 12181867. The next prime is 12181909. The reversal of 12181890 is 9818121.

12181890 = T₂₅₀ + T₂₅₁ + ... + T₄₄₅.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an alternating number because its digits alternate between odd and even.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2674 + ... + 5613.

It is an arithmetic number, because the mean of its divisors is an integer number (708624).

Almost surely, 2^12181890 is an apocalyptic number.

12181890 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

12181890 is an abundant number, since it is smaller than the sum of its proper divisors (21832062).

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

12181890 is a wasteful number, since it uses less digits than its factorization.

12181890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8311 (or 8304 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 30.

The square root of 12181890 is about 3490.2564375702. The cubic root of 12181890 is about 230.0937865784.

The spelling of 12181890 in words is "twelve million, one hundred eighty-one thousand, eight hundred ninety".