21742113 has 4 divisors (see below), whose sum is σ = 28989488. Its totient is φ = 14494740.

The previous prime is 21742111. The next prime is 21742139. The reversal of 21742113 is 31124712.

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 not a de Polignac number, because 21742113 - 2¹ = 21742111 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21742113.

It is not an unprimeable number, because it can be changed into a prime (21742111) 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, 3623683 + ... + 3623688.

It is an arithmetic number, because the mean of its divisors is an integer number (7247372).

Almost surely, 2^21742113 is an apocalyptic number.

It is an amenable number.

21742113 is a deficient number, since it is larger than the sum of its proper divisors (7247375).

21742113 is an equidigital number, since it uses as much as digits as its factorization.

21742113 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7247374.

The product of its digits is 336, while the sum is 21.

The square root of 21742113 is about 4662.8438747185. The cubic root of 21742113 is about 279.1047640376.

Adding to 21742113 its reverse (31124712), we get a palindrome (52866825).

The spelling of 21742113 in words is "twenty-one million, seven hundred forty-two thousand, one hundred thirteen".