21371263 has 2 divisors, whose sum is σ = 21371264. Its totient is φ = 21371262.

The previous prime is 21371239. The next prime is 21371267. The reversal of 21371263 is 36217312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21371263 - 2²¹ = 19274111 is a prime.

It is equal to p_1351942 and since 21371263 and 1351942 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21371267) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10685631 + 10685632.

It is an arithmetic number, because the mean of its divisors is an integer number (10685632).

Almost surely, 2^21371263 is an apocalyptic number.

21371263 is a deficient number, since it is larger than the sum of its proper divisors (1).

21371263 is an equidigital number, since it uses as much as digits as its factorization.

21371263 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1512, while the sum is 25.

The square root of 21371263 is about 4622.9063369270. The cubic root of 21371263 is about 277.5087809358.

Adding to 21371263 its reverse (36217312), we get a palindrome (57588575).

The spelling of 21371263 in words is "twenty-one million, three hundred seventy-one thousand, two hundred sixty-three".