21304045 has 16 divisors (see below), whose sum is σ = 30008448. Its totient is φ = 14212800.

The previous prime is 21304027. The next prime is 21304061. The reversal of 21304045 is 54040312.

It is not a de Polignac number, because 21304045 - 2⁷ = 21303917 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6931 + ... + 9520.

It is an arithmetic number, because the mean of its divisors is an integer number (1875528).

Almost surely, 2^21304045 is an apocalyptic number.

It is an amenable number.

21304045 is a deficient number, since it is larger than the sum of its proper divisors (8704403).

21304045 is a wasteful number, since it uses less digits than its factorization.

21304045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16500.

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 21304045 is about 4615.6305094754. The cubic root of 21304045 is about 277.2175303872.

Adding to 21304045 its reverse (54040312), we get a palindrome (75344357).

The spelling of 21304045 in words is "twenty-one million, three hundred four thousand, forty-five".