20556400 has 60 divisors (see below), whose sum is σ = 52309152. Its totient is φ = 7736320.

The previous prime is 20556397. The next prime is 20556407. The reversal of 20556400 is 465502.

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 11 ways as a sum of consecutive naturals, for example, 5289 + ... + 8311.

Almost surely, 2^20556400 is an apocalyptic number.

20556400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20556400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26154576).

20556400 is an abundant number, since it is smaller than the sum of its proper divisors (31752752).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20556400 is a wasteful number, since it uses less digits than its factorization.

20556400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3058 (or 3047 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 20556400 is about 4533.9166291409. The cubic root of 20556400 is about 273.9359432547.

The spelling of 20556400 in words is "twenty million, five hundred fifty-six thousand, four hundred".