21404519 has 4 divisors (see below), whose sum is σ = 21466200. Its totient is φ = 21342840.

The previous prime is 21404503. The next prime is 21404531. The reversal of 21404519 is 91540412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21404519 - 2⁴ = 21404503 is a prime.

It is a super-2 number, since 2×21404519² = 916306867242722, 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 (21404569) 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, 30317 + ... + 31014.

It is an arithmetic number, because the mean of its divisors is an integer number (5366550).

Almost surely, 2^21404519 is an apocalyptic number.

21404519 is a deficient number, since it is larger than the sum of its proper divisors (61681).

21404519 is an equidigital number, since it uses as much as digits as its factorization.

21404519 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61680.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 21404519 is about 4626.5018102234. The cubic root of 21404519 is about 277.6526509094.

The spelling of 21404519 in words is "twenty-one million, four hundred four thousand, five hundred nineteen".