19493921 has 4 divisors (see below), whose sum is σ = 19947312. Its totient is φ = 19040532.

The previous prime is 19493911. The next prime is 19493923. The reversal of 19493921 is 12939491.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19493921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19493923) 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, 226631 + ... + 226716.

It is an arithmetic number, because the mean of its divisors is an integer number (4986828).

Almost surely, 2^19493921 is an apocalyptic number.

It is an amenable number.

19493921 is a deficient number, since it is larger than the sum of its proper divisors (453391).

19493921 is an equidigital number, since it uses as much as digits as its factorization.

19493921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 453390.

The product of its digits is 17496, while the sum is 38.

The square root of 19493921 is about 4415.1920683024. The cubic root of 19493921 is about 269.1326579970.

The spelling of 19493921 in words is "nineteen million, four hundred ninety-three thousand, nine hundred twenty-one".