51998186520 has 480 divisors, whose sum is σ = 205272928080. Its totient is φ = 11770375680.

The previous prime is 51998186519. The next prime is 51998186549. The reversal of 51998186520 is 2568189915.

51998186520 is a `hidden beast` number, since 5 + 19 + 98 + 18 + 6 + 520 = 666.

It is a super-2 number, since 2×51998186520² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 16985790 + ... + 16988850.

Almost surely, 2^51998186520 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 51998186520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (102636464040).

51998186520 is an abundant number, since it is smaller than the sum of its proper divisors (153274741560).

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

51998186520 is a wasteful number, since it uses less digits than its factorization.

51998186520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3205 (or 3185 counting only the distinct ones).

The product of its (nonzero) digits is 1555200, while the sum is 54.

The spelling of 51998186520 in words is "fifty-one billion, nine hundred ninety-eight million, one hundred eighty-six thousand, five hundred twenty".