20168400 has 180 divisors, whose sum is σ = 75373152. Its totient is φ = 4609920.

The previous prime is 20168389. The next prime is 20168411. The reversal of 20168400 is 486102.

It is an interprime number because it is at equal distance from previous prime (20168389) and next prime (20168411).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a nialpdrome in base 7.

It is a zygodrome in base 7.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2881197 + ... + 2881203.

Almost surely, 2^20168400 is an apocalyptic number.

20168400 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 20168400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37686576).

20168400 is an abundant number, since it is smaller than the sum of its proper divisors (55204752).

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

20168400 is an frugal number, since it uses more digits than its factorization.

20168400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56 (or 17 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 20168400 is about 4490.9241810567. The cubic root of 20168400 is about 272.2014799010.

Multiplying 20168400 by its sum of digits (21), we get a square (423536400 = 20580²).

20168400 divided by its sum of digits (21) gives a square (960400 = 980²).

The spelling of 20168400 in words is "twenty million, one hundred sixty-eight thousand, four hundred".