51688780 has 144 divisors (see below), whose sum is σ = 135136512. Its totient is φ = 16473600.

The previous prime is 51688771. The next prime is 51688807. The reversal of 51688780 is 8788615.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 975234 + ... + 975286.

It is an arithmetic number, because the mean of its divisors is an integer number (938448).

Almost surely, 2^51688780 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 51688780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67568256).

51688780 is an abundant number, since it is smaller than the sum of its proper divisors (83447732).

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

51688780 is a wasteful number, since it uses less digits than its factorization.

51688780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128 (or 115 counting only the distinct ones).

The product of its (nonzero) digits is 107520, while the sum is 43.

The square root of 51688780 is about 7189.4909416453. The cubic root of 51688780 is about 372.5049891979.

The spelling of 51688780 in words is "fifty-one million, six hundred eighty-eight thousand, seven hundred eighty".