16991568 has 120 divisors (see below), whose sum is σ = 55014336. Its totient is φ = 4838400.

The previous prime is 16991561. The next prime is 16991591. The reversal of 16991568 is 86519961.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16991561) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 26613 + ... + 27243.

Almost surely, 2^16991568 is an apocalyptic number.

16991568 is a gapful number since it is divisible by the number (18) 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 16991568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27507168).

16991568 is an abundant number, since it is smaller than the sum of its proper divisors (38022768).

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

16991568 is a wasteful number, since it uses less digits than its factorization.

16991568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 673 (or 664 counting only the distinct ones).

The product of its digits is 116640, while the sum is 45.

The square root of 16991568 is about 4122.0829685973. The cubic root of 16991568 is about 257.0856401796.

The spelling of 16991568 in words is "sixteen million, nine hundred ninety-one thousand, five hundred sixty-eight".