19997393 has 4 divisors (see below), whose sum is σ = 21535668. Its totient is φ = 18459120.

The previous prime is 19997357. The next prime is 19997399. The reversal of 19997393 is 39379991.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 39379991 = 7 ⋅5625713.

It can be written as a sum of positive squares in 2 ways, for example, as 10804369 + 9193024 = 3287^2 + 3032^2 .

It is a cyclic number.

It is not a de Polignac number, because 19997393 - 2¹² = 19993297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19997399) 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, 769118 + ... + 769143.

It is an arithmetic number, because the mean of its divisors is an integer number (5383917).

Almost surely, 2^19997393 is an apocalyptic number.

19997393 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

19997393 is a deficient number, since it is larger than the sum of its proper divisors (1538275).

19997393 is a wasteful number, since it uses less digits than its factorization.

19997393 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1538274.

The product of its digits is 413343, while the sum is 50.

The square root of 19997393 is about 4471.8444740398. The cubic root of 19997393 is about 271.4299670025.

The spelling of 19997393 in words is "nineteen million, nine hundred ninety-seven thousand, three hundred ninety-three".