20556406 has 16 divisors (see below), whose sum is σ = 33297264. Its totient is φ = 9461664.

The previous prime is 20556397. The next prime is 20556407. The reversal of 20556406 is 60465502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20556407) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11296 + ... + 12988.

It is an arithmetic number, because the mean of its divisors is an integer number (2081079).

Almost surely, 2^20556406 is an apocalyptic number.

20556406 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

20556406 is a deficient number, since it is larger than the sum of its proper divisors (12740858).

20556406 is a wasteful number, since it uses less digits than its factorization.

20556406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2175.

The product of its (nonzero) digits is 7200, while the sum is 28.

The square root of 20556406 is about 4533.9172908204. The cubic root of 20556406 is about 273.9359699069.

The spelling of 20556406 in words is "twenty million, five hundred fifty-six thousand, four hundred six".