16668405 has 24 divisors (see below), whose sum is σ = 31115448. Its totient is φ = 8205696.

The previous prime is 16668403. The next prime is 16668419. The reversal of 16668405 is 50486661.

It can be written as a sum of positive squares in 4 ways, for example, as 338724 + 16329681 = 582^2 + 4041^2 .

It is not a de Polignac number, because 16668405 - 2¹ = 16668403 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 16668405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16668401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13662 + ... + 14831.

It is an arithmetic number, because the mean of its divisors is an integer number (1296477).

Almost surely, 2^16668405 is an apocalyptic number.

16668405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

16668405 is a deficient number, since it is larger than the sum of its proper divisors (14447043).

16668405 is a wasteful number, since it uses less digits than its factorization.

16668405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28517 (or 28514 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 16668405 is about 4082.6958005710. The cubic root of 16668405 is about 255.4453578307.

The spelling of 16668405 in words is "sixteen million, six hundred sixty-eight thousand, four hundred five".