21123241 has 8 divisors (see below), whose sum is σ = 21856968. Its totient is φ = 20400000.

The previous prime is 21123211. The next prime is 21123287. The reversal of 21123241 is 14232112.

It can be written as a sum of positive squares in 4 ways, for example, as 9216 + 21114025 = 96^2 + 4595^2 .

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 21123241 - 2¹⁵ = 21090473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21123211) 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, 1591 + ... + 6691.

It is an arithmetic number, because the mean of its divisors is an integer number (2732121).

Almost surely, 2^21123241 is an apocalyptic number.

It is an amenable number.

21123241 is a deficient number, since it is larger than the sum of its proper divisors (733727).

21123241 is a wasteful number, since it uses less digits than its factorization.

21123241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5243.

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

The square root of 21123241 is about 4596.0027197555. The cubic root of 21123241 is about 276.4310677965.

Adding to 21123241 its reverse (14232112), we get a palindrome (35355353).

The spelling of 21123241 in words is "twenty-one million, one hundred twenty-three thousand, two hundred forty-one".