16721564 has 12 divisors (see below), whose sum is σ = 29742888. Its totient is φ = 8223600.

The previous prime is 16721479. The next prime is 16721569. The reversal of 16721564 is 46512761.

It is a super-2 number, since 2×16721564² = 559221405212192, which contains 22 as substring.

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 self number, because there is not a number n which added to its sum of digits gives 16721564.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16721569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34022 + ... + 34509.

It is an arithmetic number, because the mean of its divisors is an integer number (2478574).

Almost surely, 2^16721564 is an apocalyptic number.

It is an amenable number.

16721564 is a deficient number, since it is larger than the sum of its proper divisors (13021324).

16721564 is a wasteful number, since it uses less digits than its factorization.

16721564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68596 (or 68594 counting only the distinct ones).

The product of its digits is 10080, while the sum is 32.

The square root of 16721564 is about 4089.2008999314. The cubic root of 16721564 is about 255.7166257304.

The spelling of 16721564 in words is "sixteen million, seven hundred twenty-one thousand, five hundred sixty-four".