16638918912 has 720 divisors, whose sum is σ = 65602196352. Its totient is φ = 4060938240.

The previous prime is 16638918893. The next prime is 16638918913. The reversal of 16638918912 is 21981983661.

16638918912 is a `hidden beast` number, since 166 + 389 + 18 + 91 + 2 = 666.

It is a super-2 number, since 2×16638918912² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (16638918913) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 27143118 + ... + 27143730.

Almost surely, 2^16638918912 is an apocalyptic number.

16638918912 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16638918912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32801098176).

16638918912 is an abundant number, since it is smaller than the sum of its proper divisors (48963277440).

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

16638918912 is a wasteful number, since it uses less digits than its factorization.

16638918912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 676 (or 653 counting only the distinct ones).

The product of its digits is 1119744, while the sum is 54.

The spelling of 16638918912 in words is "sixteen billion, six hundred thirty-eight million, nine hundred eighteen thousand, nine hundred twelve".