20405266 has 12 divisors (see below), whose sum is σ = 35605278. Its totient is φ = 8745072.

The previous prime is 20405251. The next prime is 20405269. The reversal of 20405266 is 66250402.

It can be written as a sum of positive squares in only one way, i.e., 17464041 + 2941225 = 4179^2 + 1715^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20405266.

It is not an unprimeable number, because it can be changed into a prime (20405269) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 104011 + ... + 104206.

Almost surely, 2^20405266 is an apocalyptic number.

20405266 is a deficient number, since it is larger than the sum of its proper divisors (15200012).

20405266 is a wasteful number, since it uses less digits than its factorization.

20405266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 208233 (or 208226 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 20405266 is about 4517.2188346371. The cubic root of 20405266 is about 273.2629506798.

Adding to 20405266 its reverse (66250402), we get a palindrome (86655668).

The spelling of 20405266 in words is "twenty million, four hundred five thousand, two hundred sixty-six".