19404421 has 4 divisors (see below), whose sum is σ = 19456000. Its totient is φ = 19352844.

The previous prime is 19404409. The next prime is 19404443. The reversal of 19404421 is 12440491.

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: 12440491 = 7 ⋅1777213.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19404421 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19404821) 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, 25221 + ... + 25978.

It is an arithmetic number, because the mean of its divisors is an integer number (4864000).

Almost surely, 2^19404421 is an apocalyptic number.

It is an amenable number.

19404421 is a deficient number, since it is larger than the sum of its proper divisors (51579).

19404421 is an equidigital number, since it uses as much as digits as its factorization.

19404421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51578.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 19404421 is about 4405.0449486924. The cubic root of 19404421 is about 268.7201476847.

The spelling of 19404421 in words is "nineteen million, four hundred four thousand, four hundred twenty-one".