18466991 has 4 divisors (see below), whose sum is σ = 18475752. Its totient is φ = 18458232.

The previous prime is 18466969. The next prime is 18467003. The reversal of 18466991 is 19966481.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 19966481 = 1259 ⋅15859.

It is a cyclic number.

It is not a de Polignac number, because 18466991 - 2¹⁸ = 18204847 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18466901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 920 + ... + 6146.

It is an arithmetic number, because the mean of its divisors is an integer number (4618938).

Almost surely, 2^18466991 is an apocalyptic number.

18466991 is a deficient number, since it is larger than the sum of its proper divisors (8761).

18466991 is an equidigital number, since it uses as much as digits as its factorization.

18466991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8760.

The product of its digits is 93312, while the sum is 44.

The square root of 18466991 is about 4297.3237020266. The cubic root of 18466991 is about 264.3212295379.

The spelling of 18466991 in words is "eighteen million, four hundred sixty-six thousand, nine hundred ninety-one".