21237241 has 2 divisors, whose sum is σ = 21237242. Its totient is φ = 21237240.

The previous prime is 21237239. The next prime is 21237287. The reversal of 21237241 is 14273212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19105641 + 2131600 = 4371^2 + 1460^2 .

It is a cyclic number.

It is not a de Polignac number, because 21237241 - 2¹ = 21237239 is a prime.

Together with 21237239, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21237341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10618620 + 10618621.

It is an arithmetic number, because the mean of its divisors is an integer number (10618621).

Almost surely, 2^21237241 is an apocalyptic number.

It is an amenable number.

21237241 is a deficient number, since it is larger than the sum of its proper divisors (1).

21237241 is an equidigital number, since it uses as much as digits as its factorization.

21237241 is an evil number, because the sum of its binary digits is even.

The product of its digits is 672, while the sum is 22.

The square root of 21237241 is about 4608.3881129957. The cubic root of 21237241 is about 276.9274660530.

The spelling of 21237241 in words is "twenty-one million, two hundred thirty-seven thousand, two hundred forty-one".