16621780266 has 96 divisors (see below), whose sum is σ = 44548358400. Its totient is φ = 4361651712.

The previous prime is 16621780249. The next prime is 16621780271. The reversal of 16621780266 is 66208712661.

16621780266 is a `hidden beast` number, since 16 + 621 + 7 + 8 + 0 + 2 + 6 + 6 = 666.

It is a super-2 number, since 2×16621780266² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 300466 + ... + 351458.

It is an arithmetic number, because the mean of its divisors is an integer number (464045400).

Almost surely, 2^16621780266 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16621780266, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22274179200).

16621780266 is an abundant number, since it is smaller than the sum of its proper divisors (27926578134).

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

16621780266 is a wasteful number, since it uses less digits than its factorization.

16621780266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51220 (or 51217 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The spelling of 16621780266 in words is "sixteen billion, six hundred twenty-one million, seven hundred eighty thousand, two hundred sixty-six".