51085440 has 288 divisors, whose sum is σ = 206338860. Its totient is φ = 11612160.

The previous prime is 51085417. The next prime is 51085457. The reversal of 51085440 is 4458015.

It can be written as a sum of positive squares in 2 ways, for example, as 42928704 + 8156736 = 6552^2 + 2856^2 .

It is a tau number, because it is divible by the number of its divisors (288).

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 282150 + ... + 282330.

Almost surely, 2^51085440 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 51085440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (103169430).

51085440 is an abundant number, since it is smaller than the sum of its proper divisors (155253420).

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

51085440 is a wasteful number, since it uses less digits than its factorization.

51085440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220 (or 198 counting only the distinct ones).

The product of its (nonzero) digits is 3200, while the sum is 27.

The square root of 51085440 is about 7147.4079217574. The cubic root of 51085440 is about 371.0499517410.

The spelling of 51085440 in words is "fifty-one million, eighty-five thousand, four hundred forty".