21245633 has 16 divisors (see below), whose sum is σ = 22795776. Its totient is φ = 19768320.

The previous prime is 21245617. The next prime is 21245669. The reversal of 21245633 is 33654212.

It is a cyclic number.

It is not a de Polignac number, because 21245633 - 2⁴ = 21245617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21245683) 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, 109985 + ... + 110177.

It is an arithmetic number, because the mean of its divisors is an integer number (1424736).

Almost surely, 2^21245633 is an apocalyptic number.

It is an amenable number.

21245633 is a deficient number, since it is larger than the sum of its proper divisors (1550143).

21245633 is a wasteful number, since it uses less digits than its factorization.

21245633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344.

The product of its digits is 4320, while the sum is 26.

The square root of 21245633 is about 4609.2985366539. The cubic root of 21245633 is about 276.9639376652.

Adding to 21245633 its reverse (33654212), we get a palindrome (54899845).

The spelling of 21245633 in words is "twenty-one million, two hundred forty-five thousand, six hundred thirty-three".