20180400 has 120 divisors (see below), whose sum is σ = 65870784. Its totient is φ = 5280000.

The previous prime is 20180399. The next prime is 20180441. The reversal of 20180400 is 408102.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 20180400.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 80275 + ... + 80525.

Almost surely, 2^20180400 is an apocalyptic number.

20180400 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 20180400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32935392).

20180400 is an abundant number, since it is smaller than the sum of its proper divisors (45690384).

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

20180400 is a wasteful number, since it uses less digits than its factorization.

20180400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 339 (or 328 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 20180400 is about 4492.2600102844. The cubic root of 20180400 is about 272.2554549337.

Adding to 20180400 its reverse (408102), we get a palindrome (20588502).

It can be divided in two parts, 201 and 80400, that multiplied together give a square (16160400 = 4020²).

The spelling of 20180400 in words is "twenty million, one hundred eighty thousand, four hundred".