21090459 has 8 divisors (see below), whose sum is σ = 30283792. Its totient is φ = 12978720.

The previous prime is 21090457. The next prime is 21090467. The reversal of 21090459 is 95409012.

It is a happy number.

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

It is not a de Polignac number, because 21090459 - 2¹ = 21090457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21090457) 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, 270352 + ... + 270429.

It is an arithmetic number, because the mean of its divisors is an integer number (3785474).

Almost surely, 2^21090459 is an apocalyptic number.

21090459 is a deficient number, since it is larger than the sum of its proper divisors (9193333).

21090459 is a wasteful number, since it uses less digits than its factorization.

21090459 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540797.

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 21090459 is about 4592.4349750432. The cubic root of 21090459 is about 276.2879922905.

The spelling of 21090459 in words is "twenty-one million, ninety thousand, four hundred fifty-nine".