21067001 has 4 divisors (see below), whose sum is σ = 21108900. Its totient is φ = 21025104.

The previous prime is 21066973. The next prime is 21067003. The reversal of 21067001 is 10076012.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 16000000 + 5067001 = 4000^2 + 2251^2 .

It is a cyclic number.

It is not a de Polignac number, because 21067001 - 2⁶ = 21066937 is a prime.

It is a super-2 number, since 2×21067001² = 887637062268002, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21067003) 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 3 ways as a sum of consecutive naturals, for example, 20186 + ... + 21203.

It is an arithmetic number, because the mean of its divisors is an integer number (5277225).

Almost surely, 2^21067001 is an apocalyptic number.

It is an amenable number.

21067001 is a deficient number, since it is larger than the sum of its proper divisors (41899).

21067001 is an equidigital number, since it uses as much as digits as its factorization.

21067001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41898.

The product of its (nonzero) digits is 84, while the sum is 17.

The square root of 21067001 is about 4589.8802816631. The cubic root of 21067001 is about 276.1855199179.

The spelling of 21067001 in words is "twenty-one million, sixty-seven thousand, one".