21008267 has 16 divisors (see below), whose sum is σ = 25517760. Its totient is φ = 16910208.

The previous prime is 21008263. The next prime is 21008279. The reversal of 21008267 is 76280012.

It is not a de Polignac number, because 21008267 - 2² = 21008263 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21008263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6113 + ... + 8909.

It is an arithmetic number, because the mean of its divisors is an integer number (1594860).

Almost surely, 2^21008267 is an apocalyptic number.

21008267 is a deficient number, since it is larger than the sum of its proper divisors (4509493).

21008267 is a wasteful number, since it uses less digits than its factorization.

21008267 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2870.

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 21008267 is about 4583.4776098504. The cubic root of 21008267 is about 275.9286161046.

Adding to 21008267 its reverse (76280012), we get a palindrome (97288279).

The spelling of 21008267 in words is "twenty-one million, eight thousand, two hundred sixty-seven".