19965139 has 4 divisors (see below), whose sum is σ = 19987560. Its totient is φ = 19942720.

The previous prime is 19965133. The next prime is 19965149. The reversal of 19965139 is 93156991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93156991 = 17 ⋅5479823.

It is a cyclic number.

It is not a de Polignac number, because 19965139 - 2⁵ = 19965107 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19965095 and 19965104.

It is not an unprimeable number, because it can be changed into a prime (19965133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9817 + ... + 11674.

It is an arithmetic number, because the mean of its divisors is an integer number (4996890).

Almost surely, 2^19965139 is an apocalyptic number.

19965139 is a deficient number, since it is larger than the sum of its proper divisors (22421).

19965139 is an equidigital number, since it uses as much as digits as its factorization.

19965139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22420.

The product of its digits is 65610, while the sum is 43.

The square root of 19965139 is about 4468.2366768111. The cubic root of 19965139 is about 271.2839577497.

The spelling of 19965139 in words is "nineteen million, nine hundred sixty-five thousand, one hundred thirty-nine".