21342613 has 4 divisors (see below), whose sum is σ = 21554028. Its totient is φ = 21131200.

The previous prime is 21342583. The next prime is 21342631. The reversal of 21342613 is 31624312.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19158129 + 2184484 = 4377^2 + 1478^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21342613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21342683) 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, 105556 + ... + 105757.

It is an arithmetic number, because the mean of its divisors is an integer number (5388507).

Almost surely, 2^21342613 is an apocalyptic number.

It is an amenable number.

21342613 is a deficient number, since it is larger than the sum of its proper divisors (211415).

21342613 is a wasteful number, since it uses less digits than its factorization.

21342613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211414.

The product of its digits is 864, while the sum is 22.

The square root of 21342613 is about 4619.8065976835. The cubic root of 21342613 is about 277.3847174203.

Adding to 21342613 its reverse (31624312), we get a palindrome (52966925).

The spelling of 21342613 in words is "twenty-one million, three hundred forty-two thousand, six hundred thirteen".