51409540 has 96 divisors (see below), whose sum is σ = 135926784. Its totient is φ = 15897600.

The previous prime is 51409511. The next prime is 51409543. The reversal of 51409540 is 4590415.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a junction number, because it is equal to n+sod(n) for n = 51409499 and 51409508.

It is not an unprimeable number, because it can be changed into a prime (51409543) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 85240 + ... + 85840.

It is an arithmetic number, because the mean of its divisors is an integer number (1415904).

Almost surely, 2^51409540 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 51409540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67963392).

51409540 is an abundant number, since it is smaller than the sum of its proper divisors (84517244).

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

51409540 is a wasteful number, since it uses less digits than its factorization.

51409540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 677 (or 675 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 51409540 is about 7170.0446302656. The cubic root of 51409540 is about 371.8329789395.

Adding to 51409540 its reverse (4590415), we get a palindrome (55999955).

The spelling of 51409540 in words is "fifty-one million, four hundred nine thousand, five hundred forty".