16443621 has 16 divisors (see below), whose sum is σ = 24822720. Its totient is φ = 10754640.

The previous prime is 16443619. The next prime is 16443629. The reversal of 16443621 is 12634461.

It is not a de Polignac number, because 16443621 - 2¹ = 16443619 is a prime.

It is a super-3 number, since 3×16443621³ (a number of 23 digits) contains 333 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16443629) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4315 + ... + 7176.

It is an arithmetic number, because the mean of its divisors is an integer number (1551420).

Almost surely, 2^16443621 is an apocalyptic number.

It is an amenable number.

16443621 is a deficient number, since it is larger than the sum of its proper divisors (8379099).

16443621 is a wasteful number, since it uses less digits than its factorization.

16443621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11553 (or 11547 counting only the distinct ones).

The product of its digits is 3456, while the sum is 27.

The square root of 16443621 is about 4055.0734888532. The cubic root of 16443621 is about 254.2918762221.

The spelling of 16443621 in words is "sixteen million, four hundred forty-three thousand, six hundred twenty-one".