16991721600 has 384 divisors, whose sum is σ = 64428912000. Its totient is φ = 3855482880.

The previous prime is 16991721599. The next prime is 16991721611. The reversal of 16991721600 is 612719961.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (42).

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, 10011952 + ... + 10013648.

It is an arithmetic number, because the mean of its divisors is an integer number (167783625).

Almost surely, 2^16991721600 is an apocalyptic number.

16991721600 is a gapful number since it is divisible by the number (10) 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 16991721600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32214456000).

16991721600 is an abundant number, since it is smaller than the sum of its proper divisors (47437190400).

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

16991721600 is a wasteful number, since it uses less digits than its factorization.

16991721600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1880 (or 1863 counting only the distinct ones).

The product of its (nonzero) digits is 40824, while the sum is 42.

The spelling of 16991721600 in words is "sixteen billion, nine hundred ninety-one million, seven hundred twenty-one thousand, six hundred".