16561600 has 84 divisors (see below), whose sum is σ = 44503848. Its totient is φ = 6016000.

The previous prime is 16561591. The next prime is 16561603. The reversal of 16561600 is 616561.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16561603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17130 + ... + 18070.

Almost surely, 2^16561600 is an apocalyptic number.

16561600 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 16561600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22251924).

16561600 is an abundant number, since it is smaller than the sum of its proper divisors (27942248).

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

16561600 is a wasteful number, since it uses less digits than its factorization.

16561600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 974 (or 959 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 16561600 is about 4069.5945744017. The cubic root of 16561600 is about 254.8985884073.

It can be divided in two parts, 16561 and 600, that added together give a square (17161 = 131²).

The spelling of 16561600 in words is "sixteen million, five hundred sixty-one thousand, six hundred".