51551240 has 32 divisors (see below), whose sum is σ = 124913880. Its totient is φ = 19034112.

The previous prime is 51551221. The next prime is 51551243. The reversal of 51551240 is 4215515.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 17422276 + 34128964 = 4174^2 + 5842^2 .

It is not an unprimeable number, because it can be changed into a prime (51551243) 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, 49049 + ... + 50088.

Almost surely, 2^51551240 is an apocalyptic number.

It is an amenable number.

51551240 is an abundant number, since it is smaller than the sum of its proper divisors (73362640).

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

51551240 is a wasteful number, since it uses less digits than its factorization.

51551240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99161 (or 99157 counting only the distinct ones).

The product of its (nonzero) digits is 1000, while the sum is 23.

The square root of 51551240 is about 7179.9192196013. The cubic root of 51551240 is about 372.1742930127.

Adding to 51551240 its reverse (4215515), we get a palindrome (55766755).

The spelling of 51551240 in words is "fifty-one million, five hundred fifty-one thousand, two hundred forty".