51502240 has 24 divisors (see below), whose sum is σ = 121674420. Its totient is φ = 20600832.

The previous prime is 51502207. The next prime is 51502249. The reversal of 51502240 is 4220515.

It can be written as a sum of positive squares in 2 ways, for example, as 47389456 + 4112784 = 6884^2 + 2028^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51502249) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 160785 + ... + 161104.

Almost surely, 2^51502240 is an apocalyptic number.

It is an amenable number.

51502240 is an abundant number, since it is smaller than the sum of its proper divisors (70172180).

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

51502240 is a wasteful number, since it uses less digits than its factorization.

51502240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 321904 (or 321896 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 51502240 is about 7176.5061137018. The cubic root of 51502240 is about 372.0563370953.

Adding to 51502240 its reverse (4220515), we get a palindrome (55722755).

The spelling of 51502240 in words is "fifty-one million, five hundred two thousand, two hundred forty".