21042113 has 8 divisors (see below), whose sum is σ = 21665448. Its totient is φ = 20427264.

The previous prime is 21042103. The next prime is 21042127. The reversal of 21042113 is 31124012.

It can be written as a sum of positive squares in 4 ways, for example, as 3794704 + 17247409 = 1948^2 + 4153^2 .

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 21042113 - 2⁴ = 21042097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21042103) 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, 3095 + ... + 7187.

It is an arithmetic number, because the mean of its divisors is an integer number (2708181).

Almost surely, 2^21042113 is an apocalyptic number.

It is an amenable number.

21042113 is a deficient number, since it is larger than the sum of its proper divisors (623335).

21042113 is an equidigital number, since it uses as much as digits as its factorization.

21042113 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4243.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 21042113 is about 4587.1682986348. The cubic root of 21042113 is about 276.0767176288.

Adding to 21042113 its reverse (31124012), we get a palindrome (52166125).

The spelling of 21042113 in words is "twenty-one million, forty-two thousand, one hundred thirteen".