16561040 has 20 divisors (see below), whose sum is σ = 38504604. Its totient is φ = 6624384.

The previous prime is 16561033. The next prime is 16561049. The reversal of 16561040 is 4016561.

It can be written as a sum of positive squares in 2 ways, for example, as 6801664 + 9759376 = 2608^2 + 3124^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 16560997 and 16561015.

It is not an unprimeable number, because it can be changed into a prime (16561049) 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 3 ways as a sum of consecutive naturals, for example, 103427 + ... + 103586.

Almost surely, 2^16561040 is an apocalyptic number.

16561040 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16561040 is an abundant number, since it is smaller than the sum of its proper divisors (21943564).

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

16561040 is a wasteful number, since it uses less digits than its factorization.

16561040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 207026 (or 207020 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 16561040 is about 4069.5257708976. The cubic root of 16561040 is about 254.8957153994.

The spelling of 16561040 in words is "sixteen million, five hundred sixty-one thousand, forty".