21267613 has 2 divisors, whose sum is σ = 21267614. Its totient is φ = 21267612.

The previous prime is 21267583. The next prime is 21267619. The reversal of 21267613 is 31676212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17665209 + 3602404 = 4203^2 + 1898^2 .

It is a cyclic number.

It is not a de Polignac number, because 21267613 - 2¹⁷ = 21136541 is a prime.

It is a super-2 number, since 2×21267613² = 904622725435538, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21267619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10633806 + 10633807.

It is an arithmetic number, because the mean of its divisors is an integer number (10633807).

Almost surely, 2^21267613 is an apocalyptic number.

It is an amenable number.

21267613 is a deficient number, since it is larger than the sum of its proper divisors (1).

21267613 is an equidigital number, since it uses as much as digits as its factorization.

21267613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 28.

The square root of 21267613 is about 4611.6822310302. The cubic root of 21267613 is about 277.0594171957.

The spelling of 21267613 in words is "twenty-one million, two hundred sixty-seven thousand, six hundred thirteen".