51551966520 has 96 divisors (see below), whose sum is σ = 167962176720. Its totient is φ = 13712870400.

The previous prime is 51551966513. The next prime is 51551966537. The reversal of 51551966520 is 2566915515.

51551966520 is a `hidden beast` number, since 5 + 1 + 55 + 19 + 66 + 520 = 666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

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 polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 34194 + ... + 322913.

Almost surely, 2^51551966520 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 51551966520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83981088360).

51551966520 is an abundant number, since it is smaller than the sum of its proper divisors (116410210200).

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

51551966520 is a wasteful number, since it uses less digits than its factorization.

51551966520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357525 (or 357518 counting only the distinct ones).

The product of its (nonzero) digits is 405000, while the sum is 45.

The spelling of 51551966520 in words is "fifty-one billion, five hundred fifty-one million, nine hundred sixty-six thousand, five hundred twenty".