16661633 has 4 divisors (see below), whose sum is σ = 16671060. Its totient is φ = 16652208.

The previous prime is 16661629. The next prime is 16661681. The reversal of 16661633 is 33616661.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 4355569 + 12306064 = 2087^2 + 3508^2 .

It is a cyclic number.

It is not a de Polignac number, because 16661633 - 2² = 16661629 is a prime.

It is a super-2 number, since 2×16661633² = 555220028453378, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 16661633.

It is not an unprimeable number, because it can be changed into a prime (16601633) 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, 1178 + ... + 5891.

It is an arithmetic number, because the mean of its divisors is an integer number (4167765).

Almost surely, 2^16661633 is an apocalyptic number.

16661633 is the 2357-th octagonal number.

It is an amenable number.

16661633 is a deficient number, since it is larger than the sum of its proper divisors (9427).

16661633 is an equidigital number, since it uses as much as digits as its factorization.

16661633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9426.

The product of its digits is 11664, while the sum is 32.

The square root of 16661633 is about 4081.8663623397. The cubic root of 16661633 is about 255.4107592336.

The spelling of 16661633 in words is "sixteen million, six hundred sixty-one thousand, six hundred thirty-three".