21345611 has 8 divisors (see below), whose sum is σ = 24498144. Its totient is φ = 18218880.

The previous prime is 21345593. The next prime is 21345619. The reversal of 21345611 is 11654312.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21345611 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21345619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4640 + ... + 8013.

It is an arithmetic number, because the mean of its divisors is an integer number (3062268).

Almost surely, 2^21345611 is an apocalyptic number.

21345611 is a deficient number, since it is larger than the sum of its proper divisors (3152533).

21345611 is a wasteful number, since it uses less digits than its factorization.

21345611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12901.

The product of its digits is 720, while the sum is 23.

The square root of 21345611 is about 4620.1310587471. The cubic root of 21345611 is about 277.3977049030.

Adding to 21345611 its reverse (11654312), we get a palindrome (32999923).

The spelling of 21345611 in words is "twenty-one million, three hundred forty-five thousand, six hundred eleven".