51213120840 has 384 divisors, whose sum is σ = 203017052160. Its totient is φ = 10929364992.

The previous prime is 51213120793. The next prime is 51213120853. The reversal of 51213120840 is 4802131215.

It is an unprimeable number.

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 95 ways as a sum of consecutive naturals, for example, 5435974 + ... + 5445386.

It is an arithmetic number, because the mean of its divisors is an integer number (528690240).

Almost surely, 2^51213120840 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 51213120840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (101508526080).

51213120840 is an abundant number, since it is smaller than the sum of its proper divisors (151803931320).

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

51213120840 is a wasteful number, since it uses less digits than its factorization.

51213120840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9581 (or 9574 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The spelling of 51213120840 in words is "fifty-one billion, two hundred thirteen million, one hundred twenty thousand, eight hundred forty".