21025233 has 6 divisors (see below), whose sum is σ = 30369794. Its totient is φ = 14016816.

The previous prime is 21025217. The next prime is 21025273. The reversal of 21025233 is 33252012.

It can be written as a sum of positive squares in only one way, i.e., 18766224 + 2259009 = 4332^2 + 1503^2 .

It is not a de Polignac number, because 21025233 - 2⁴ = 21025217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21025273) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1168060 + ... + 1168077.

Almost surely, 2^21025233 is an apocalyptic number.

It is an amenable number.

21025233 is a deficient number, since it is larger than the sum of its proper divisors (9344561).

21025233 is a wasteful number, since it uses less digits than its factorization.

21025233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2336143 (or 2336140 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

The square root of 21025233 is about 4585.3280144391. The cubic root of 21025233 is about 276.0028748913.

Adding to 21025233 its reverse (33252012), we get a palindrome (54277245).

The spelling of 21025233 in words is "twenty-one million, twenty-five thousand, two hundred thirty-three".