20266021 has 4 divisors (see below), whose sum is σ = 20310444. Its totient is φ = 20221600.

The previous prime is 20266007. The next prime is 20266039. The reversal of 20266021 is 12066202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12066202 = 2 ⋅6033101.

It can be written as a sum of positive squares in 2 ways, for example, as 11937025 + 8328996 = 3455^2 + 2886^2 .

It is a cyclic number.

It is not a de Polignac number, because 20266021 - 2⁷ = 20265893 is a prime.

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 20266021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20266721) 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, 21520 + ... + 22441.

It is an arithmetic number, because the mean of its divisors is an integer number (5077611).

Almost surely, 2^20266021 is an apocalyptic number.

It is an amenable number.

20266021 is a deficient number, since it is larger than the sum of its proper divisors (44423).

20266021 is an equidigital number, since it uses as much as digits as its factorization.

20266021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44422.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 20266021 is about 4501.7797591619. The cubic root of 20266021 is about 272.6399516778.

The spelling of 20266021 in words is "twenty million, two hundred sixty-six thousand, twenty-one".