51431440 has 40 divisors (see below), whose sum is σ = 122367168. Its totient is φ = 20092800.

The previous prime is 51431407. The next prime is 51431441. The reversal of 51431440 is 4413415.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (51431441) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 4036 + ... + 10915.

Almost surely, 2^51431440 is an apocalyptic number.

It is an amenable number.

51431440 is an abundant number, since it is smaller than the sum of its proper divisors (70935728).

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

51431440 is a wasteful number, since it uses less digits than its factorization.

51431440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15007 (or 15001 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 22.

The square root of 51431440 is about 7171.5716548048. The cubic root of 51431440 is about 371.8857706082.

Adding to 51431440 its reverse (4413415), we get a palindrome (55844855).

The spelling of 51431440 in words is "fifty-one million, four hundred thirty-one thousand, four hundred forty".