20405335266 has 64 divisors (see below), whose sum is σ = 47865600000. Its totient is φ = 6425724816.

The previous prime is 20405335217. The next prime is 20405335267. The reversal of 20405335266 is 66253350402.

20405335266 is a `hidden beast` number, since 20 + 40 + 5 + 335 + 266 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 20405335266.

It is not an unprimeable number, because it can be changed into a prime (20405335267) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 340635 + ... + 396033.

It is an arithmetic number, because the mean of its divisors is an integer number (747900000).

Almost surely, 2^20405335266 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20405335266, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23932800000).

20405335266 is an abundant number, since it is smaller than the sum of its proper divisors (27460264734).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20405335266 is a wasteful number, since it uses less digits than its factorization.

20405335266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55788 (or 55782 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 36.

Adding to 20405335266 its reverse (66253350402), we get a palindrome (86658685668).

The spelling of 20405335266 in words is "twenty billion, four hundred five million, three hundred thirty-five thousand, two hundred sixty-six".