21673511 has 2 divisors, whose sum is σ = 21673512. Its totient is φ = 21673510.

The previous prime is 21673459. The next prime is 21673517. The reversal of 21673511 is 11537612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21673511 - 2¹⁰ = 21672487 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 (21673517) 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, 10836755 + 10836756.

It is an arithmetic number, because the mean of its divisors is an integer number (10836756).

Almost surely, 2^21673511 is an apocalyptic number.

21673511 is a deficient number, since it is larger than the sum of its proper divisors (1).

21673511 is an equidigital number, since it uses as much as digits as its factorization.

21673511 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1260, while the sum is 26.

The square root of 21673511 is about 4655.4818225400. The cubic root of 21673511 is about 278.8109054713.

The spelling of 21673511 in words is "twenty-one million, six hundred seventy-three thousand, five hundred eleven".