20855405 has 16 divisors (see below), whose sum is σ = 26002944. Its totient is φ = 16040640.

The previous prime is 20855377. The next prime is 20855423. The reversal of 20855405 is 50455802.

It is not a de Polignac number, because 20855405 - 2¹⁶ = 20789869 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30194 + ... + 30876.

It is an arithmetic number, because the mean of its divisors is an integer number (1625184).

Almost surely, 2^20855405 is an apocalyptic number.

It is an amenable number.

20855405 is a deficient number, since it is larger than the sum of its proper divisors (5147539).

20855405 is a wasteful number, since it uses less digits than its factorization.

20855405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 916.

The product of its (nonzero) digits is 8000, while the sum is 29.

The square root of 20855405 is about 4566.7718357720. The cubic root of 20855405 is about 275.2577418289.

The spelling of 20855405 in words is "twenty million, eight hundred fifty-five thousand, four hundred five".