51611521328640 has 1920 divisors, whose sum is σ = 222640182116352. Its totient is φ = 10759416053760.

The previous prime is 51611521328599. The next prime is 51611521328663. The reversal of 51611521328640 is 4682312511615.

51611521328640 is a `hidden beast` number, since 5 + 1 + 6 + 1 + 1 + 521 + 3 + 2 + 86 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (1920).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 78080969910 + ... + 78080970570.

Almost surely, 2^{51611521328640} 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 51611521328640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (111320091058176).

51611521328640 is an abundant number, since it is smaller than the sum of its proper divisors (171028660787712).

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

51611521328640 is a wasteful number, since it uses less digits than its factorization.

51611521328640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1100 (or 1081 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

The spelling of 51611521328640 in words is "fifty-one trillion, six hundred eleven billion, five hundred twenty-one million, three hundred twenty-eight thousand, six hundred forty".