21235245 has 16 divisors (see below), whose sum is σ = 34618752. Its totient is φ = 11111360.

The previous prime is 21235243. The next prime is 21235273. The reversal of 21235245 is 54253212.

It is not a de Polignac number, because 21235245 - 2¹ = 21235243 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21235243) 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, 12561 + ... + 14150.

It is an arithmetic number, because the mean of its divisors is an integer number (2163672).

Almost surely, 2^21235245 is an apocalyptic number.

It is an amenable number.

21235245 is a deficient number, since it is larger than the sum of its proper divisors (13383507).

21235245 is a wasteful number, since it uses less digits than its factorization.

21235245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26772.

The product of its digits is 2400, while the sum is 24.

The square root of 21235245 is about 4608.1715462860. The cubic root of 21235245 is about 276.9187900274.

Adding to 21235245 its reverse (54253212), we get a palindrome (75488457).

The spelling of 21235245 in words is "twenty-one million, two hundred thirty-five thousand, two hundred forty-five".