51438291840 has 640 divisors, whose sum is σ = 199715281920. Its totient is φ = 12541132800.

The previous prime is 51438291799. The next prime is 51438291851. The reversal of 51438291840 is 4819283415.

51438291840 is a `hidden beast` number, since 51 + 438 + 2 + 91 + 84 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

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 pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 85587540 + ... + 85588140.

It is an arithmetic number, because the mean of its divisors is an integer number (312055128).

Almost surely, 2^51438291840 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 51438291840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99857640960).

51438291840 is an abundant number, since it is smaller than the sum of its proper divisors (148276990080).

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

51438291840 is a wasteful number, since it uses less digits than its factorization.

51438291840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 772 (or 751 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The spelling of 51438291840 in words is "fifty-one billion, four hundred thirty-eight million, two hundred ninety-one thousand, eight hundred forty".