51549361864 has 192 divisors, whose sum is σ = 131152129920. Its totient is φ = 18483379200.

The previous prime is 51549361861. The next prime is 51549361879. The reversal of 51549361864 is 46816394515.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (52).

It is not an unprimeable number, because it can be changed into a prime (51549361861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 39022324 + ... + 39023644.

It is an arithmetic number, because the mean of its divisors is an integer number (683084010).

Almost surely, 2^51549361864 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 51549361864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (65576064960).

51549361864 is an abundant number, since it is smaller than the sum of its proper divisors (79602768056).

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

51549361864 is a wasteful number, since it uses less digits than its factorization.

51549361864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1812 (or 1797 counting only the distinct ones).

The product of its digits is 3110400, while the sum is 52.

The spelling of 51549361864 in words is "fifty-one billion, five hundred forty-nine million, three hundred sixty-one thousand, eight hundred sixty-four".