21604267 has 2 divisors, whose sum is σ = 21604268. Its totient is φ = 21604266.

The previous prime is 21604249. The next prime is 21604301. The reversal of 21604267 is 76240612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21604267 - 2⁷ = 21604139 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21604967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10802133 + 10802134.

It is an arithmetic number, because the mean of its divisors is an integer number (10802134).

Almost surely, 2^21604267 is an apocalyptic number.

21604267 is a deficient number, since it is larger than the sum of its proper divisors (1).

21604267 is an equidigital number, since it uses as much as digits as its factorization.

21604267 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 21604267 is about 4648.0390488893. The cubic root of 21604267 is about 278.5136673830.

Adding to 21604267 its reverse (76240612), we get a palindrome (97844879).

The spelling of 21604267 in words is "twenty-one million, six hundred four thousand, two hundred sixty-seven".