21104431 has 8 divisors (see below), whose sum is σ = 21942000. Its totient is φ = 20274240.

The previous prime is 21104407. The next prime is 21104453. The reversal of 21104431 is 13440112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21104431 - 2⁵ = 21104399 is a prime.

It is a super-2 number, since 2×21104431² = 890794015667522, 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 (21104401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4395 + ... + 7843.

It is an arithmetic number, because the mean of its divisors is an integer number (2742750).

Almost surely, 2^21104431 is an apocalyptic number.

21104431 is a deficient number, since it is larger than the sum of its proper divisors (837569).

21104431 is a wasteful number, since it uses less digits than its factorization.

21104431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3689.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 21104431 is about 4593.9559205547. The cubic root of 21104431 is about 276.3489905470.

Adding to 21104431 its reverse (13440112), we get a palindrome (34544543).

The spelling of 21104431 in words is "twenty-one million, one hundred four thousand, four hundred thirty-one".