18142993 has 4 divisors (see below), whose sum is σ = 19792368. Its totient is φ = 16493620.

The previous prime is 18142991. The next prime is 18143003. The reversal of 18142993 is 39924181.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 39924181 = 11 ⋅3629471.

It is not a de Polignac number, because 18142993 - 2¹ = 18142991 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18142991) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 824671 + ... + 824692.

It is an arithmetic number, because the mean of its divisors is an integer number (4948092).

Almost surely, 2^18142993 is an apocalyptic number.

It is an amenable number.

18142993 is a deficient number, since it is larger than the sum of its proper divisors (1649375).

18142993 is a wasteful number, since it uses less digits than its factorization.

18142993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1649374.

The product of its digits is 15552, while the sum is 37.

The square root of 18142993 is about 4259.4592379785. The cubic root of 18142993 is about 262.7662869985.

The spelling of 18142993 in words is "eighteen million, one hundred forty-two thousand, nine hundred ninety-three".