20400000 has 192 divisors, whose sum is σ = 71714160. Its totient is φ = 5120000.

The previous prime is 20399993. The next prime is 20400013. The reversal of 20400000 is 402.

It is a tau number, because it is divible by the number of its divisors (192).

It is a Harshad number since it is a multiple of its sum of digits (6).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1199992 + ... + 1200008.

Almost surely, 2^20400000 is an apocalyptic number.

20400000 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 20400000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35857080).

20400000 is an abundant number, since it is smaller than the sum of its proper divisors (51314160).

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

20400000 is an frugal number, since it uses more digits than its factorization.

20400000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59 (or 27 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 6.

The square root of 20400000 is about 4516.6359162545. The cubic root of 20400000 is about 273.2394416094.

Adding to 20400000 its reverse (402), we get a palindrome (20400402).

It can be divided in two parts, 20 and 400000, that multiplied together give a cube (8000000 = 200³).

The spelling of 20400000 in words is "twenty million, four hundred thousand".