19523989 has 4 divisors (see below), whose sum is σ = 20197260. Its totient is φ = 18850720.

The previous prime is 19523983. The next prime is 19523993. The reversal of 19523989 is 98932591.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98932591 = 23 ⋅4301417.

It can be written as a sum of positive squares in 2 ways, for example, as 16337764 + 3186225 = 4042^2 + 1785^2 .

It is a cyclic number.

It is not a de Polignac number, because 19523989 - 2¹¹ = 19521941 is a prime.

It is a super-2 number, since 2×19523989² = 762372292944242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19523983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 336592 + ... + 336649.

It is an arithmetic number, because the mean of its divisors is an integer number (5049315).

Almost surely, 2^19523989 is an apocalyptic number.

It is an amenable number.

19523989 is a deficient number, since it is larger than the sum of its proper divisors (673271).

19523989 is an equidigital number, since it uses as much as digits as its factorization.

19523989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 673270.

The product of its digits is 174960, while the sum is 46.

The square root of 19523989 is about 4418.5958176778. The cubic root of 19523989 is about 269.2709596370.

The spelling of 19523989 in words is "nineteen million, five hundred twenty-three thousand, nine hundred eighty-nine".