21134521 has 2 divisors, whose sum is σ = 21134522. Its totient is φ = 21134520.

The previous prime is 21134513. The next prime is 21134527. The reversal of 21134521 is 12543112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11148921 + 9985600 = 3339^2 + 3160^2 .

It is a cyclic number.

It is not a de Polignac number, because 21134521 - 2³ = 21134513 is a prime.

It is not a weakly prime, because it can be changed into another prime (21134527) 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, 10567260 + 10567261.

It is an arithmetic number, because the mean of its divisors is an integer number (10567261).

Almost surely, 2^21134521 is an apocalyptic number.

It is an amenable number.

21134521 is a deficient number, since it is larger than the sum of its proper divisors (1).

21134521 is an equidigital number, since it uses as much as digits as its factorization.

21134521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 240, while the sum is 19.

The square root of 21134521 is about 4597.2297092923. The cubic root of 21134521 is about 276.4802645962.

Adding to 21134521 its reverse (12543112), we get a palindrome (33677633).

The spelling of 21134521 in words is "twenty-one million, one hundred thirty-four thousand, five hundred twenty-one".