51508440 has 128 divisors (see below), whose sum is σ = 176472000. Its totient is φ = 13353984.

The previous prime is 51508439. The next prime is 51508447. The reversal of 51508440 is 4480515.

51508440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51508447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 39316 + ... + 40604.

Almost surely, 2^51508440 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 51508440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88236000).

51508440 is an abundant number, since it is smaller than the sum of its proper divisors (124963560).

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

51508440 is a wasteful number, since it uses less digits than its factorization.

51508440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1346 (or 1336 counting only the distinct ones).

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

The square root of 51508440 is about 7176.9380657771. The cubic root of 51508440 is about 372.0712662630.

Adding to 51508440 its reverse (4480515), we get a palindrome (55988955).

The spelling of 51508440 in words is "fifty-one million, five hundred eight thousand, four hundred forty".