16643965 has 12 divisors (see below), whose sum is σ = 21628404. Its totient is φ = 12290304.

The previous prime is 16643947. The next prime is 16643971. The reversal of 16643965 is 56934661.

It can be written as a sum of positive squares in 6 ways, for example, as 6365529 + 10278436 = 2523^2 + 3206^2 .

It is not a de Polignac number, because 16643965 - 2⁵ = 16643933 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9004 + ... + 10693.

It is an arithmetic number, because the mean of its divisors is an integer number (1802367).

Almost surely, 2^16643965 is an apocalyptic number.

It is an amenable number.

16643965 is a deficient number, since it is larger than the sum of its proper divisors (4984439).

16643965 is a wasteful number, since it uses less digits than its factorization.

16643965 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19728 (or 19715 counting only the distinct ones).

The product of its digits is 116640, while the sum is 40.

The square root of 16643965 is about 4079.7015822239. The cubic root of 16643965 is about 255.3204480920.

The spelling of 16643965 in words is "sixteen million, six hundred forty-three thousand, nine hundred sixty-five".