18420243 has 16 divisors (see below), whose sum is σ = 25178496. Its totient is φ = 11975040.

The previous prime is 18420239. The next prime is 18420247. The reversal of 18420243 is 34202481.

It is an interprime number because it is at equal distance from previous prime (18420239) and next prime (18420247).

It is not a de Polignac number, because 18420243 - 2² = 18420239 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18420247) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22308 + ... + 23118.

It is an arithmetic number, because the mean of its divisors is an integer number (1573656).

Almost surely, 2^18420243 is an apocalyptic number.

18420243 is a deficient number, since it is larger than the sum of its proper divisors (6758253).

18420243 is a wasteful number, since it uses less digits than its factorization.

18420243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 994.

The product of its (nonzero) digits is 1536, while the sum is 24.

The square root of 18420243 is about 4291.8810561338. The cubic root of 18420243 is about 264.0980036737.

The spelling of 18420243 in words is "eighteen million, four hundred twenty thousand, two hundred forty-three".