18203993 has 8 divisors (see below), whose sum is σ = 18717312. Its totient is φ = 17696016.

The previous prime is 18203947. The next prime is 18204029. The reversal of 18203993 is 39930281.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18203993 - 2⁶ = 18203929 is a prime.

It is a super-2 number, since 2×18203993² = 662770722288098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18203693) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6146 + ... + 8612.

It is an arithmetic number, because the mean of its divisors is an integer number (2339664).

Almost surely, 2^18203993 is an apocalyptic number.

It is an amenable number.

18203993 is a deficient number, since it is larger than the sum of its proper divisors (513319).

18203993 is a wasteful number, since it uses less digits than its factorization.

18203993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2671.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 18203993 is about 4266.6137626928. The cubic root of 18203993 is about 263.0604467171.

The spelling of 18203993 in words is "eighteen million, two hundred three thousand, nine hundred ninety-three".