21090441 has 8 divisors (see below), whose sum is σ = 28806624. Its totient is φ = 13717280.

The previous prime is 21090439. The next prime is 21090457. The reversal of 21090441 is 14409012.

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 21090441 - 2¹ = 21090439 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21090401) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85611 + ... + 85856.

It is an arithmetic number, because the mean of its divisors is an integer number (3600828).

Almost surely, 2^21090441 is an apocalyptic number.

It is an amenable number.

21090441 is a deficient number, since it is larger than the sum of its proper divisors (7716183).

21090441 is a wasteful number, since it uses less digits than its factorization.

21090441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171511.

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21090441 is about 4592.4330152981. The cubic root of 21090441 is about 276.2879136896.

Adding to 21090441 its reverse (14409012), we get a palindrome (35499453).

The spelling of 21090441 in words is "twenty-one million, ninety thousand, four hundred forty-one".