51005009640 has 128 divisors (see below), whose sum is σ = 164907187200. Its totient is φ = 12545802240.

The previous prime is 51005009597. The next prime is 51005009641. The reversal of 51005009640 is 4690050015.

It is a super-2 number, since 2×51005009640² (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 a junction number, because it is equal to n+sod(n) for n = 51005009598 and 51005009607.

It is not an unprimeable number, because it can be changed into a prime (51005009641) 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 31 ways as a sum of consecutive naturals, for example, 2233480 + ... + 2256200.

It is an arithmetic number, because the mean of its divisors is an integer number (1288337400).

Almost surely, 2^51005009640 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 51005009640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (82453593600).

51005009640 is an abundant number, since it is smaller than the sum of its proper divisors (113902177560).

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

51005009640 is a wasteful number, since it uses less digits than its factorization.

51005009640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24187 (or 24183 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 30.

Adding to 51005009640 its reverse (4690050015), we get a palindrome (55695059655).

The spelling of 51005009640 in words is "fifty-one billion, five million, nine thousand, six hundred forty".