16557640 has 64 divisors (see below), whose sum is σ = 41109120. Its totient is φ = 6001600.

The previous prime is 16557601. The next prime is 16557659. The reversal of 16557640 is 4675561.

It is a happy number.

16557640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 16557596 and 16557605.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53085 + ... + 53395.

It is an arithmetic number, because the mean of its divisors is an integer number (642330).

Almost surely, 2^16557640 is an apocalyptic number.

16557640 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 16557640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20554560).

16557640 is an abundant number, since it is smaller than the sum of its proper divisors (24551480).

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

16557640 is a wasteful number, since it uses less digits than its factorization.

16557640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355 (or 329 counting only the distinct ones).

The product of its (nonzero) digits is 25200, while the sum is 34.

The square root of 16557640 is about 4069.1080103630. The cubic root of 16557640 is about 254.8782707473.

The spelling of 16557640 in words is "sixteen million, five hundred fifty-seven thousand, six hundred forty".