21527213 has 2 divisors, whose sum is σ = 21527214. Its totient is φ = 21527212.

The previous prime is 21527183. The next prime is 21527227. The reversal of 21527213 is 31272512.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18130564 + 3396649 = 4258^2 + 1843^2 .

It is a cyclic number.

It is not a de Polignac number, because 21527213 - 2¹⁶ = 21461677 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21527713) 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, 10763606 + 10763607.

It is an arithmetic number, because the mean of its divisors is an integer number (10763607).

Almost surely, 2^21527213 is an apocalyptic number.

It is an amenable number.

21527213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21527213 is an equidigital number, since it uses as much as digits as its factorization.

21527213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 840, while the sum is 23.

The square root of 21527213 is about 4639.7427730425. The cubic root of 21527213 is about 278.1821563801.

Adding to 21527213 its reverse (31272512), we get a palindrome (52799725).

The spelling of 21527213 in words is "twenty-one million, five hundred twenty-seven thousand, two hundred thirteen".