21521067 has 4 divisors (see below), whose sum is σ = 28694760. Its totient is φ = 14347376.

The previous prime is 21521051. The next prime is 21521083. The reversal of 21521067 is 76012512.

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

It is an interprime number because it is at equal distance from previous prime (21521051) and next prime (21521083).

It is a cyclic number.

It is not a de Polignac number, because 21521067 - 2⁴ = 21521051 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21526067) 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, 3586842 + ... + 3586847.

It is an arithmetic number, because the mean of its divisors is an integer number (7173690).

Almost surely, 2^21521067 is an apocalyptic number.

21521067 is a deficient number, since it is larger than the sum of its proper divisors (7173693).

21521067 is an equidigital number, since it uses as much as digits as its factorization.

21521067 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7173692.

The product of its (nonzero) digits is 840, while the sum is 24.

The square root of 21521067 is about 4639.0804045630. The cubic root of 21521067 is about 278.1556802750.

Adding to 21521067 its reverse (76012512), we get a palindrome (97533579).

The spelling of 21521067 in words is "twenty-one million, five hundred twenty-one thousand, sixty-seven".