20400646266 has 384 divisors, whose sum is σ = 61953196032. Its totient is φ = 4681152000.

The previous prime is 20400646223. The next prime is 20400646271. The reversal of 20400646266 is 66264600402.

20400646266 is a `hidden beast` number, since 2 + 0 + 4 + 0 + 0 + 646 + 2 + 6 + 6 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 20400646266.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 47333071 + ... + 47333501.

It is an arithmetic number, because the mean of its divisors is an integer number (161336448).

Almost surely, 2^20400646266 is an apocalyptic number.

20400646266 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 20400646266, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30976598016).

20400646266 is an abundant number, since it is smaller than the sum of its proper divisors (41552549766).

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

20400646266 is a wasteful number, since it uses less digits than its factorization.

20400646266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 578 (or 575 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 36.

It can be divided in two parts, 20400 and 646266, that added together give a palindrome (666666).

The spelling of 20400646266 in words is "twenty billion, four hundred million, six hundred forty-six thousand, two hundred sixty-six".