51505440 has 96 divisors (see below), whose sum is σ = 185431680. Its totient is φ = 11771904.

The previous prime is 51505423. The next prime is 51505481. The reversal of 51505440 is 4450515.

51505440 = 873² + 874² + ... + 935².

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 51505440.

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, 4305 + ... + 11024.

It is an arithmetic number, because the mean of its divisors is an integer number (1931580).

Almost surely, 2^51505440 is an apocalyptic number.

It is an amenable number.

51505440 is an abundant number, since it is smaller than the sum of its proper divisors (133926240).

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

51505440 is a wasteful number, since it uses less digits than its factorization.

51505440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15354 (or 15346 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 24.

The square root of 51505440 is about 7176.7290599548. The cubic root of 51505440 is about 372.0640426218.

Adding to 51505440 its reverse (4450515), we get a palindrome (55955955).

The spelling of 51505440 in words is "fifty-one million, five hundred five thousand, four hundred forty".