20403855 has 24 divisors (see below), whose sum is σ = 36232560. Its totient is φ = 10615680.

The previous prime is 20403847. The next prime is 20403857. The reversal of 20403855 is 55830402.

It is not a de Polignac number, because 20403855 - 2³ = 20403847 is a prime.

It is a super-3 number, since 3×20403855³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20403857) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3685 + ... + 7374.

It is an arithmetic number, because the mean of its divisors is an integer number (1509690).

Almost surely, 2^20403855 is an apocalyptic number.

20403855 is a deficient number, since it is larger than the sum of its proper divisors (15828705).

20403855 is a wasteful number, since it uses less digits than its factorization.

20403855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11111 (or 11108 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 20403855 is about 4517.0626517683. The cubic root of 20403855 is about 273.2566519314.

The spelling of 20403855 in words is "twenty million, four hundred three thousand, eight hundred fifty-five".