51415540 has 48 divisors (see below), whose sum is σ = 118984320. Its totient is φ = 18506880.

The previous prime is 51415523. The next prime is 51415543. The reversal of 51415540 is 4551415.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51415543) 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 15 ways as a sum of consecutive naturals, for example, 21526 + ... + 23794.

It is an arithmetic number, because the mean of its divisors is an integer number (2478840).

Almost surely, 2^51415540 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 51415540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (59492160).

51415540 is an abundant number, since it is smaller than the sum of its proper divisors (67568780).

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

51415540 is a wasteful number, since it uses less digits than its factorization.

51415540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2392 (or 2390 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 25.

The square root of 51415540 is about 7170.4630254956. The cubic root of 51415540 is about 371.8474439012.

Adding to 51415540 its reverse (4551415), we get a palindrome (55966955).

The spelling of 51415540 in words is "fifty-one million, four hundred fifteen thousand, five hundred forty".