21303345 has 16 divisors (see below), whose sum is σ = 38954880. Its totient is φ = 9738624.

The previous prime is 21303341. The next prime is 21303349. The reversal of 21303345 is 54330312.

It is an interprime number because it is at equal distance from previous prime (21303341) and next prime (21303349).

It is not a de Polignac number, because 21303345 - 2² = 21303341 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21303341) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 101340 + ... + 101549.

It is an arithmetic number, because the mean of its divisors is an integer number (2434680).

Almost surely, 2^21303345 is an apocalyptic number.

It is an amenable number.

21303345 is a deficient number, since it is larger than the sum of its proper divisors (17651535).

21303345 is a wasteful number, since it uses less digits than its factorization.

21303345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202904.

The product of its (nonzero) digits is 1080, while the sum is 21.

The square root of 21303345 is about 4615.5546795591. The cubic root of 21303345 is about 277.2144941187.

Adding to 21303345 its reverse (54330312), we get a palindrome (75633657).

The spelling of 21303345 in words is "twenty-one million, three hundred three thousand, three hundred forty-five".