21080267 has 4 divisors (see below), whose sum is σ = 22701840. Its totient is φ = 19458696.

The previous prime is 21080261. The next prime is 21080317. The reversal of 21080267 is 76208012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21080267 - 2⁶ = 21080203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21080261) 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 3 ways as a sum of consecutive naturals, for example, 810767 + ... + 810792.

It is an arithmetic number, because the mean of its divisors is an integer number (5675460).

Almost surely, 2^21080267 is an apocalyptic number.

21080267 is a deficient number, since it is larger than the sum of its proper divisors (1621573).

21080267 is a wasteful number, since it uses less digits than its factorization.

21080267 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1621572.

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

The square root of 21080267 is about 4591.3251899642. The cubic root of 21080267 is about 276.2434795728.

Adding to 21080267 its reverse (76208012), we get a palindrome (97288279).

The spelling of 21080267 in words is "twenty-one million, eighty thousand, two hundred sixty-seven".