51081162640 has 80 divisors (see below), whose sum is σ = 122807139840. Its totient is φ = 19739105280.

The previous prime is 51081162611. The next prime is 51081162647. The reversal of 51081162640 is 4626118015.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 51081162596 and 51081162605.

It is not an unprimeable number, because it can be changed into a prime (51081162647) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 1438216 + ... + 1473304.

It is an arithmetic number, because the mean of its divisors is an integer number (1535089248).

Almost surely, 2^51081162640 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 51081162640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (61403569920).

51081162640 is an abundant number, since it is smaller than the sum of its proper divisors (71725977200).

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

51081162640 is a wasteful number, since it uses less digits than its factorization.

51081162640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35720 (or 35714 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 34.

The spelling of 51081162640 in words is "fifty-one billion, eighty-one million, one hundred sixty-two thousand, six hundred forty".