16621265664 has 288 divisors, whose sum is σ = 52538976000. Its totient is φ = 5167742976.

The previous prime is 16621265663. The next prime is 16621265693. The reversal of 16621265664 is 46656212661.

16621265664 is a `hidden beast` number, since 1 + 6 + 62 + 1 + 26 + 566 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is not an unprimeable number, because it can be changed into a prime (16621265663) 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, 8798032 + ... + 8799920.

It is an arithmetic number, because the mean of its divisors is an integer number (182427000).

Almost surely, 2^16621265664 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16621265664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26269488000).

16621265664 is an abundant number, since it is smaller than the sum of its proper divisors (35917710336).

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

16621265664 is a wasteful number, since it uses less digits than its factorization.

16621265664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2000 (or 1980 counting only the distinct ones).

The product of its digits is 622080, while the sum is 45.

It can be divided in two parts, 16621265 and 664, that added together give a square (16621929 = 4077²).

The spelling of 16621265664 in words is "sixteen billion, six hundred twenty-one million, two hundred sixty-five thousand, six hundred sixty-four".