51311131650 has 72 divisors (see below), whose sum is σ = 138012398784. Its totient is φ = 13667436000.

The previous prime is 51311131621. The next prime is 51311131657. The reversal of 51311131650 is 5613111315.

It is a happy number.

51311131650 is a `hidden beast` number, since 5 + 1 + 3 + 1 + 1 + 1 + 3 + 1 + 650 = 666.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51311131657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 334875 + ... + 463425.

It is an arithmetic number, because the mean of its divisors is an integer number (1916838872).

Almost surely, 2^51311131650 is an apocalyptic number.

51311131650 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 51311131650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (69006199392).

51311131650 is an abundant number, since it is smaller than the sum of its proper divisors (86701267134).

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

51311131650 is a wasteful number, since it uses less digits than its factorization.

51311131650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129456 (or 129448 counting only the distinct ones).

The product of its (nonzero) digits is 1350, while the sum is 27.

Adding to 51311131650 its reverse (5613111315), we get a palindrome (56924242965).

The spelling of 51311131650 in words is "fifty-one billion, three hundred eleven million, one hundred thirty-one thousand, six hundred fifty".