20120400 has 240 divisors, whose sum is σ = 75649920. Its totient is φ = 5132160.

The previous prime is 20120383. The next prime is 20120407. The reversal of 20120400 is 402102.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20120407) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 874789 + ... + 874811.

It is an arithmetic number, because the mean of its divisors is an integer number (315208).

Almost surely, 2^20120400 is an apocalyptic number.

20120400 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 20120400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37824960).

20120400 is an abundant number, since it is smaller than the sum of its proper divisors (55529520).

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

20120400 is an equidigital number, since it uses as much as digits as its factorization.

20120400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62 (or 33 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

The square root of 20120400 is about 4485.5768859758. The cubic root of 20120400 is about 271.9853654179.

Adding to 20120400 its reverse (402102), we get a palindrome (20522502).

The spelling of 20120400 in words is "twenty million, one hundred twenty thousand, four hundred".