21351267 has 12 divisors (see below), whose sum is σ = 35246640. Its totient is φ = 12200688.

The previous prime is 21351241. The next prime is 21351287. The reversal of 21351267 is 76215312.

It is a happy number.

It is not a de Polignac number, because 21351267 - 2¹¹ = 21349219 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21351267.

It is not an unprimeable number, because it can be changed into a prime (21351217) 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 in 11 ways as a sum of consecutive naturals, for example, 169392 + ... + 169517.

It is an arithmetic number, because the mean of its divisors is an integer number (2937220).

Almost surely, 2^21351267 is an apocalyptic number.

21351267 is a deficient number, since it is larger than the sum of its proper divisors (13895373).

21351267 is a wasteful number, since it uses less digits than its factorization.

21351267 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 338922 (or 338919 counting only the distinct ones).

The product of its digits is 2520, while the sum is 27.

The square root of 21351267 is about 4620.7431220530. The cubic root of 21351267 is about 277.4222036608.

Adding to 21351267 its reverse (76215312), we get a palindrome (97566579).

The spelling of 21351267 in words is "twenty-one million, three hundred fifty-one thousand, two hundred sixty-seven".