51031240 has 48 divisors (see below), whose sum is σ = 124348500. Its totient is φ = 18839808.

The previous prime is 51031231. The next prime is 51031241. The reversal of 51031240 is 4213015.

It can be written as a sum of positive squares in 6 ways, for example, as 12068676 + 38962564 = 3474^2 + 6242^2 .

It is not an unprimeable number, because it can be changed into a prime (51031241) 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 11 ways as a sum of consecutive naturals, for example, 2986 + ... + 10534.

Almost surely, 2^51031240 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 51031240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (62174250).

51031240 is an abundant number, since it is smaller than the sum of its proper divisors (73317260).

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

51031240 is a wasteful number, since it uses less digits than its factorization.

51031240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7586 (or 7569 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 51031240 is about 7143.6153311891. The cubic root of 51031240 is about 370.9186813052.

Adding to 51031240 its reverse (4213015), we get a palindrome (55244255).

The spelling of 51031240 in words is "fifty-one million, thirty-one thousand, two hundred forty".