21525223 has 2 divisors, whose sum is σ = 21525224. Its totient is φ = 21525222.

The previous prime is 21525199. The next prime is 21525227. The reversal of 21525223 is 32252512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21525223 - 2¹³ = 21517031 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21525194 and 21525203.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21525227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10762611 + 10762612.

It is an arithmetic number, because the mean of its divisors is an integer number (10762612).

Almost surely, 2^21525223 is an apocalyptic number.

21525223 is a deficient number, since it is larger than the sum of its proper divisors (1).

21525223 is an equidigital number, since it uses as much as digits as its factorization.

21525223 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1200, while the sum is 22.

The square root of 21525223 is about 4639.5283165425. The cubic root of 21525223 is about 278.1735842912.

Adding to 21525223 its reverse (32252512), we get a palindrome (53777735).

It can be divided in two parts, 2 and 1525223, that added together give a square (1525225 = 1235²).

The spelling of 21525223 in words is "twenty-one million, five hundred twenty-five thousand, two hundred twenty-three".