51331540 has 48 divisors (see below), whose sum is σ = 122209920. Its totient is φ = 17953920.

The previous prime is 51331513. The next prime is 51331573. The reversal of 51331540 is 4513315.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 256 + ... + 10135.

It is an arithmetic number, because the mean of its divisors is an integer number (2546040).

Almost surely, 2^51331540 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 51331540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (61104960).

51331540 is an abundant number, since it is smaller than the sum of its proper divisors (70878380).

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

51331540 is a wasteful number, since it uses less digits than its factorization.

51331540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10432 (or 10430 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 22.

The square root of 51331540 is about 7164.6032688489. The cubic root of 51331540 is about 371.6448319355.

Adding to 51331540 its reverse (4513315), we get a palindrome (55844855).

The spelling of 51331540 in words is "fifty-one million, three hundred thirty-one thousand, five hundred forty".