18928993 has 4 divisors (see below), whose sum is σ = 18982080. Its totient is φ = 18875908.

The previous prime is 18928991. The next prime is 18929017. The reversal of 18928993 is 39982981.

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.

It is a cyclic number.

It is not a de Polignac number, because 18928993 - 2¹ = 18928991 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18928991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26005 + ... + 26722.

It is an arithmetic number, because the mean of its divisors is an integer number (4745520).

Almost surely, 2^18928993 is an apocalyptic number.

It is an amenable number.

18928993 is a deficient number, since it is larger than the sum of its proper divisors (53087).

18928993 is an equidigital number, since it uses as much as digits as its factorization.

18928993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53086.

The product of its digits is 279936, while the sum is 49.

The square root of 18928993 is about 4350.7462578275. The cubic root of 18928993 is about 266.5073372873.

The spelling of 18928993 in words is "eighteen million, nine hundred twenty-eight thousand, nine hundred ninety-three".