21066101 has 4 divisors (see below), whose sum is σ = 24075552. Its totient is φ = 18056652.

The previous prime is 21066049. The next prime is 21066107. The reversal of 21066101 is 10166012.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21066101 - 2¹⁸ = 20803957 is a prime.

It is a super-2 number, since 2×21066101² = 887561222684402, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21066101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21066107) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1504715 + ... + 1504728.

It is an arithmetic number, because the mean of its divisors is an integer number (6018888).

Almost surely, 2^21066101 is an apocalyptic number.

It is an amenable number.

21066101 is a deficient number, since it is larger than the sum of its proper divisors (3009451).

21066101 is an equidigital number, since it uses as much as digits as its factorization.

21066101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3009450.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 21066101 is about 4589.7822388431. The cubic root of 21066101 is about 276.1815869027.

The spelling of 21066101 in words is "twenty-one million, sixty-six thousand, one hundred one".