51205404125540 has 144 divisors (see below), whose sum is σ = 132471322648560. Its totient is φ = 16520212316160.

The previous prime is 51205404125539. The next prime is 51205404125633. The reversal of 51205404125540 is 4552140450215.

It can be written as a sum of positive squares in 8 ways, for example, as 5290469210404 + 45914934915136 = 2300102^2 + 6776056^2 .

It is a junction number, because it is equal to n+sod(n) for n = 51205404125494 and 51205404125503.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 86152580 + ... + 86744900.

It is an arithmetic number, because the mean of its divisors is an integer number (919939740615).

Almost surely, 2^{51205404125540} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51205404125540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (66235661324280).

51205404125540 is an abundant number, since it is smaller than the sum of its proper divisors (81265918523020).

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

51205404125540 is a wasteful number, since it uses less digits than its factorization.

51205404125540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 597550 (or 597541 counting only the distinct ones).

The product of its (nonzero) digits is 160000, while the sum is 38.

Adding to 51205404125540 its reverse (4552140450215), we get a palindrome (55757544575755).

The spelling of 51205404125540 in words is "fifty-one trillion, two hundred five billion, four hundred four million, one hundred twenty-five thousand, five hundred forty".