21242013 has 8 divisors (see below), whose sum is σ = 30501408. Its totient is φ = 13071984.

The previous prime is 21241991. The next prime is 21242047. The reversal of 21242013 is 31024212.

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

It is not a de Polignac number, because 21242013 - 2⁹ = 21241501 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21241983 and 21242001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242063) 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, 272295 + ... + 272372.

It is an arithmetic number, because the mean of its divisors is an integer number (3812676).

Almost surely, 2^21242013 is an apocalyptic number.

It is an amenable number.

21242013 is a deficient number, since it is larger than the sum of its proper divisors (9259395).

21242013 is a wasteful number, since it uses less digits than its factorization.

21242013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 544683.

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21242013 is about 4608.9058354451. The cubic root of 21242013 is about 276.9482063319.

Adding to 21242013 its reverse (31024212), we get a palindrome (52266225).

The spelling of 21242013 in words is "twenty-one million, two hundred forty-two thousand, thirteen".