51017021520 has 80 divisors (see below), whose sum is σ = 160833366720. Its totient is φ = 13373949952.

The previous prime is 51017021509. The next prime is 51017021569. The reversal of 51017021520 is 2512071015.

51017021520 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×51017021520² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1787289 + ... + 1815608.

It is an arithmetic number, because the mean of its divisors is an integer number (2010417084).

Almost surely, 2^51017021520 is an apocalyptic number.

It is an amenable number.

51017021520 is an abundant number, since it is smaller than the sum of its proper divisors (109816345200).

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

51017021520 is a wasteful number, since it uses less digits than its factorization.

51017021520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3602972 (or 3602966 counting only the distinct ones).

The product of its (nonzero) digits is 700, while the sum is 24.

Adding to 51017021520 its reverse (2512071015), we get a palindrome (53529092535).

The spelling of 51017021520 in words is "fifty-one billion, seventeen million, twenty-one thousand, five hundred twenty".