20405169 has 16 divisors (see below), whose sum is σ = 30374400. Its totient is φ = 13538448.

The previous prime is 20405153. The next prime is 20405173. The reversal of 20405169 is 96150402.

It is not a de Polignac number, because 20405169 - 2⁴ = 20405153 is a prime.

It is a super-2 number, since 2×20405169² = 832741843837122, which contains 22 as substring.

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20405129) 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, 4327 + ... + 7715.

It is an arithmetic number, because the mean of its divisors is an integer number (1898400).

Almost surely, 2^20405169 is an apocalyptic number.

It is an amenable number.

20405169 is a deficient number, since it is larger than the sum of its proper divisors (9969231).

20405169 is a wasteful number, since it uses less digits than its factorization.

20405169 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3621 (or 3615 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 20405169 is about 4517.2080979295. The cubic root of 20405169 is about 273.2625176781.

The spelling of 20405169 in words is "twenty million, four hundred five thousand, one hundred sixty-nine".