51805505664 has 320 divisors, whose sum is σ = 173625281280. Its totient is φ = 15191193600.

The previous prime is 51805505657. The next prime is 51805505671. The reversal of 51805505664 is 46650550815.

51805505664 is a `hidden beast` number, since 5 + 1 + 80 + 5 + 5 + 0 + 566 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (51805505657) and next prime (51805505671).

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 3528162 + ... + 3542814.

It is an arithmetic number, because the mean of its divisors is an integer number (542579004).

Almost surely, 2^51805505664 is an apocalyptic number.

51805505664 is a gapful number since it is divisible by the number (54) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51805505664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86812640640).

51805505664 is an abundant number, since it is smaller than the sum of its proper divisors (121819775616).

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

51805505664 is a wasteful number, since it uses less digits than its factorization.

51805505664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14721 (or 14700 counting only the distinct ones).

The product of its (nonzero) digits is 720000, while the sum is 45.

The spelling of 51805505664 in words is "fifty-one billion, eight hundred five million, five hundred five thousand, six hundred sixty-four".