19665493 has 2 divisors, whose sum is σ = 19665494. Its totient is φ = 19665492.

The previous prime is 19665473. The next prime is 19665511. The reversal of 19665493 is 39456691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10381284 + 9284209 = 3222^2 + 3047^2 .

It is a cyclic number.

It is not a de Polignac number, because 19665493 - 2¹³ = 19657301 is a prime.

It is a super-2 number, since 2×19665493² = 773463229866098, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19665473) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9832746 + 9832747.

It is an arithmetic number, because the mean of its divisors is an integer number (9832747).

Almost surely, 2^19665493 is an apocalyptic number.

It is an amenable number.

19665493 is a deficient number, since it is larger than the sum of its proper divisors (1).

19665493 is an equidigital number, since it uses as much as digits as its factorization.

19665493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 174960, while the sum is 43.

The square root of 19665493 is about 4434.5792359591. The cubic root of 19665493 is about 269.9199259575.

The spelling of 19665493 in words is "nineteen million, six hundred sixty-five thousand, four hundred ninety-three".