21240113 has 4 divisors (see below), whose sum is σ = 21380928. Its totient is φ = 21099300.

The previous prime is 21240101. The next prime is 21240133. The reversal of 21240113 is 31104212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21240113 - 2⁴ = 21240097 is a prime.

It is a super-2 number, since 2×21240113² = 902284800505538, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21240133) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70181 + ... + 70482.

It is an arithmetic number, because the mean of its divisors is an integer number (5345232).

Almost surely, 2^21240113 is an apocalyptic number.

It is an amenable number.

21240113 is a deficient number, since it is larger than the sum of its proper divisors (140815).

21240113 is a wasteful number, since it uses less digits than its factorization.

21240113 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140814.

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

The square root of 21240113 is about 4608.6997081606. The cubic root of 21240113 is about 276.9399488395.

Adding to 21240113 its reverse (31104212), we get a palindrome (52344325).

The spelling of 21240113 in words is "twenty-one million, two hundred forty thousand, one hundred thirteen".