16391664 has 60 divisors (see below), whose sum is σ = 46425600. Its totient is φ = 5398272.

The previous prime is 16391659. The next prime is 16391671. The reversal of 16391664 is 46619361.

16391664 is a `hidden beast` number, since 1 + 639 + 16 + 6 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12177 + ... + 13455.

It is an arithmetic number, because the mean of its divisors is an integer number (773760).

Almost surely, 2^16391664 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 16391664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23212800).

16391664 is an abundant number, since it is smaller than the sum of its proper divisors (30033936).

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

16391664 is a wasteful number, since it uses less digits than its factorization.

16391664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1382 (or 1373 counting only the distinct ones).

The product of its digits is 23328, while the sum is 36.

The square root of 16391664 is about 4048.6620012048. The cubic root of 16391664 is about 254.0237644907.

The spelling of 16391664 in words is "sixteen million, three hundred ninety-one thousand, six hundred sixty-four".