19813231 has 2 divisors, whose sum is σ = 19813232. Its totient is φ = 19813230.

The previous prime is 19813223. The next prime is 19813237. The reversal of 19813231 is 13231891.

It is a strong prime.

It is an emirp because it is prime and its reverse (13231891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19813231 - 2³ = 19813223 is a prime.

It is a super-3 number, since 3×19813231³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 19813231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19813237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9906615 + 9906616.

It is an arithmetic number, because the mean of its divisors is an integer number (9906616).

Almost surely, 2^19813231 is an apocalyptic number.

19813231 is a deficient number, since it is larger than the sum of its proper divisors (1).

19813231 is an equidigital number, since it uses as much as digits as its factorization.

19813231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1296, while the sum is 28.

The square root of 19813231 is about 4451.2055670346. The cubic root of 19813231 is about 270.5941693193.

The spelling of 19813231 in words is "nineteen million, eight hundred thirteen thousand, two hundred thirty-one".