20455405 has 4 divisors (see below), whose sum is σ = 24546492. Its totient is φ = 16364320.

The previous prime is 20455397. The next prime is 20455417. The reversal of 20455405 is 50455402.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50455402 = 2 ⋅25227701.

It can be written as a sum of positive squares in 2 ways, for example, as 2452356 + 18003049 = 1566^2 + 4243^2 .

It is not a de Polignac number, because 20455405 - 2³ = 20455397 is a prime.

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 20455405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2045536 + ... + 2045545.

It is an arithmetic number, because the mean of its divisors is an integer number (6136623).

Almost surely, 2^20455405 is an apocalyptic number.

It is an amenable number.

20455405 is a deficient number, since it is larger than the sum of its proper divisors (4091087).

20455405 is an equidigital number, since it uses as much as digits as its factorization.

20455405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4091086.

The product of its (nonzero) digits is 4000, while the sum is 25.

The square root of 20455405 is about 4522.7651939936. The cubic root of 20455405 is about 273.4865845271.

The spelling of 20455405 in words is "twenty million, four hundred fifty-five thousand, four hundred five".