51312040400 has 120 divisors (see below), whose sum is σ = 125541964800. Its totient is φ = 20148736000.

The previous prime is 51312040369. The next prime is 51312040453. The reversal of 51312040400 is 404021315.

It is a super-2 number, since 2×51312040400² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

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, 27162656 + ... + 27164544.

It is an arithmetic number, because the mean of its divisors is an integer number (1046183040).

Almost surely, 2^51312040400 is an apocalyptic number.

51312040400 is a gapful number since it is divisible by the number (50) 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 51312040400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (62770982400).

51312040400 is an abundant number, since it is smaller than the sum of its proper divisors (74229924400).

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

51312040400 is a wasteful number, since it uses less digits than its factorization.

51312040400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3117 (or 3106 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

Adding to 51312040400 its reverse (404021315), we get a palindrome (51716061715).

The spelling of 51312040400 in words is "fifty-one billion, three hundred twelve million, forty thousand, four hundred".