51521440 has 24 divisors (see below), whose sum is σ = 121719780. Its totient is φ = 20608512.

The previous prime is 51521423. The next prime is 51521443. The reversal of 51521440 is 4412515.

It can be written as a sum of positive squares in 2 ways, for example, as 47941776 + 3579664 = 6924^2 + 1892^2 .

It is not an unprimeable number, because it can be changed into a prime (51521443) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 160845 + ... + 161164.

Almost surely, 2^51521440 is an apocalyptic number.

It is an amenable number.

51521440 is an abundant number, since it is smaller than the sum of its proper divisors (70198340).

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

51521440 is a wasteful number, since it uses less digits than its factorization.

51521440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322024 (or 322016 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 22.

The square root of 51521440 is about 7177.8436873479. The cubic root of 51521440 is about 372.1025654675.

Adding to 51521440 its reverse (4412515), we get a palindrome (55933955).

The spelling of 51521440 in words is "fifty-one million, five hundred twenty-one thousand, four hundred forty".