51121335720 has 512 divisors, whose sum is σ = 197188992000. Its totient is φ = 10311598080.

The previous prime is 51121335701. The next prime is 51121335743. The reversal of 51121335720 is 2753312115.

It is a super-2 number, since 2×51121335720² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 34517380 + ... + 34518860.

It is an arithmetic number, because the mean of its divisors is an integer number (385134750).

Almost surely, 2^51121335720 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 51121335720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (98594496000).

51121335720 is an abundant number, since it is smaller than the sum of its proper divisors (146067656280).

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

51121335720 is a wasteful number, since it uses less digits than its factorization.

51121335720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1653 (or 1649 counting only the distinct ones).

The product of its (nonzero) digits is 6300, while the sum is 30.

Adding to 51121335720 its reverse (2753312115), we get a palindrome (53874647835).

The spelling of 51121335720 in words is "fifty-one billion, one hundred twenty-one million, three hundred thirty-five thousand, seven hundred twenty".