16561904 has 20 divisors (see below), whose sum is σ = 32170560. Its totient is φ = 8259840.

The previous prime is 16561889. The next prime is 16561913. The reversal of 16561904 is 40916561.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6584 + ... + 8744.

It is an arithmetic number, because the mean of its divisors is an integer number (1608528).

Almost surely, 2^16561904 is an apocalyptic number.

It is an amenable number.

16561904 is a deficient number, since it is larger than the sum of its proper divisors (15608656).

16561904 is a wasteful number, since it uses less digits than its factorization.

16561904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2648 (or 2642 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 16561904 is about 4069.6319243882. The cubic root of 16561904 is about 254.9001480129.

The spelling of 16561904 in words is "sixteen million, five hundred sixty-one thousand, nine hundred four".