19217993 has 4 divisors (see below), whose sum is σ = 19228308. Its totient is φ = 19207680.

The previous prime is 19217969. The next prime is 19218013. The reversal of 19217993 is 39971291.

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: 39971291 = 47 ⋅850453.

It can be written as a sum of positive squares in 2 ways, for example, as 1138489 + 18079504 = 1067^2 + 4252^2 .

It is a cyclic number.

It is not a de Polignac number, because 19217993 - 2⁶ = 19217929 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19217993.

It is not an unprimeable number, because it can be changed into a prime (19210993) 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, 1496 + ... + 6377.

It is an arithmetic number, because the mean of its divisors is an integer number (4807077).

Almost surely, 2^19217993 is an apocalyptic number.

It is an amenable number.

19217993 is a deficient number, since it is larger than the sum of its proper divisors (10315).

19217993 is an equidigital number, since it uses as much as digits as its factorization.

19217993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10314.

The product of its digits is 30618, while the sum is 41.

The square root of 19217993 is about 4383.8331400727. The cubic root of 19217993 is about 267.8568004940.

The spelling of 19217993 in words is "nineteen million, two hundred seventeen thousand, nine hundred ninety-three".