51455440 has 40 divisors (see below), whose sum is σ = 120070440. Its totient is φ = 20507136.

The previous prime is 51455431. The next prime is 51455441. The reversal of 51455440 is 4455415.

51455440 is a nontrivial binomial coefficient, being equal to C(10145, 2).

It can be written as a sum of positive squares in 4 ways, for example, as 7683984 + 43771456 = 2772^2 + 6616^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a junction number, because it is equal to n+sod(n) for n = 51455399 and 51455408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51455441) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24346 + ... + 26374.

It is an arithmetic number, because the mean of its divisors is an integer number (3001761).

Almost surely, 2^51455440 is an apocalyptic number.

51455440 is the 10144-th triangular number.

51455440 is the 3382-nd centered nonagonal number.

It is an amenable number.

51455440 is an abundant number, since it is smaller than the sum of its proper divisors (68615000).

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

51455440 is a wasteful number, since it uses less digits than its factorization.

51455440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2359 (or 2353 counting only the distinct ones).

The product of its (nonzero) digits is 8000, while the sum is 28.

The square root of 51455440 is about 7173.2447330340. The cubic root of 51455440 is about 371.9436072839.

It can be divided in two parts, 5145 and 5440, that added together give a triangular number (10585 = T₁₄₅).

The spelling of 51455440 in words is "fifty-one million, four hundred fifty-five thousand, four hundred forty".