19871923 has 4 divisors (see below), whose sum is σ = 20409040. Its totient is φ = 19334808.

The previous prime is 19871911. The next prime is 19871927. The reversal of 19871923 is 32917891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32917891 = 109 ⋅301999.

It is a cyclic number.

It is not a de Polignac number, because 19871923 - 2¹³ = 19863731 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19871927) 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, 268503 + ... + 268576.

It is an arithmetic number, because the mean of its divisors is an integer number (5102260).

Almost surely, 2^19871923 is an apocalyptic number.

19871923 is a deficient number, since it is larger than the sum of its proper divisors (537117).

19871923 is an equidigital number, since it uses as much as digits as its factorization.

19871923 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 537116.

The product of its digits is 27216, while the sum is 40.

The square root of 19871923 is about 4457.7935124902. The cubic root of 19871923 is about 270.8610962835.

The spelling of 19871923 in words is "nineteen million, eight hundred seventy-one thousand, nine hundred twenty-three".