51565556 has 48 divisors (see below), whose sum is σ = 110186496. Its totient is φ = 20611584.

The previous prime is 51565543. The next prime is 51565571. The reversal of 51565556 is 65556515.

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, 60026 + ... + 60878.

It is an arithmetic number, because the mean of its divisors is an integer number (2295552).

Almost surely, 2^51565556 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 51565556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55093248).

51565556 is an abundant number, since it is smaller than the sum of its proper divisors (58620940).

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

51565556 is a wasteful number, since it uses less digits than its factorization.

51565556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1008 (or 1006 counting only the distinct ones).

The product of its digits is 112500, while the sum is 38.

The square root of 51565556 is about 7180.9160975463. The cubic root of 51565556 is about 372.2087412888.

The spelling of 51565556 in words is "fifty-one million, five hundred sixty-five thousand, five hundred fifty-six".