19425921 has 4 divisors (see below), whose sum is σ = 25901232. Its totient is φ = 12950612.

The previous prime is 19425919. The next prime is 19425947. The reversal of 19425921 is 12952491.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12952491 = 3 ⋅4317497.

It is a cyclic number.

It is not a de Polignac number, because 19425921 - 2¹ = 19425919 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19425971) 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, 3237651 + ... + 3237656.

It is an arithmetic number, because the mean of its divisors is an integer number (6475308).

Almost surely, 2^19425921 is an apocalyptic number.

It is an amenable number.

19425921 is a deficient number, since it is larger than the sum of its proper divisors (6475311).

19425921 is an equidigital number, since it uses as much as digits as its factorization.

19425921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6475310.

The product of its digits is 6480, while the sum is 33.

The square root of 19425921 is about 4407.4846568082. The cubic root of 19425921 is about 268.8193579056.

The spelling of 19425921 in words is "nineteen million, four hundred twenty-five thousand, nine hundred twenty-one".