51555780 has 36 divisors (see below), whose sum is σ = 156386412. Its totient is φ = 13748160.

The previous prime is 51555773. The next prime is 51555827. The reversal of 51555780 is 8755515.

It can be written as a sum of positive squares in 2 ways, for example, as 40144896 + 11410884 = 6336^2 + 3378^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 143031 + ... + 143390.

It is an arithmetic number, because the mean of its divisors is an integer number (4344067).

Almost surely, 2^51555780 is an apocalyptic number.

It is an amenable number.

51555780 is an abundant number, since it is smaller than the sum of its proper divisors (104830632).

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

51555780 is a wasteful number, since it uses less digits than its factorization.

51555780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 286436 (or 286431 counting only the distinct ones).

The product of its (nonzero) digits is 35000, while the sum is 36.

The square root of 51555780 is about 7180.2353721866. The cubic root of 51555780 is about 372.1852182054.

The spelling of 51555780 in words is "fifty-one million, five hundred fifty-five thousand, seven hundred eighty".