51561051066 has 80 divisors (see below), whose sum is σ = 132881417856. Its totient is φ = 14637845664.

The previous prime is 51561051053. The next prime is 51561051083. The reversal of 51561051066 is 66015016515.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 51561051066.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 33235 + ... + 322841.

Almost surely, 2^51561051066 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51561051066, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (66440708928).

51561051066 is an abundant number, since it is smaller than the sum of its proper divisors (81320366790).

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

51561051066 is a wasteful number, since it uses less digits than its factorization.

51561051066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289785 (or 289776 counting only the distinct ones).

The product of its (nonzero) digits is 27000, while the sum is 36.

The spelling of 51561051066 in words is "fifty-one billion, five hundred sixty-one million, fifty-one thousand, sixty-six".