51305040 has 60 divisors (see below), whose sum is σ = 172301844. Its totient is φ = 13681152.

The previous prime is 51305017. The next prime is 51305047. The reversal of 51305040 is 4050315.

It can be written as a sum of positive squares in 2 ways, for example, as 31270464 + 20034576 = 5592^2 + 4476^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51305047) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34909 + ... + 36348.

Almost surely, 2^51305040 is an apocalyptic number.

It is an amenable number.

51305040 is an abundant number, since it is smaller than the sum of its proper divisors (120996804).

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

51305040 is a wasteful number, since it uses less digits than its factorization.

51305040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71276 (or 71267 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 51305040 is about 7162.7536604298. The cubic root of 51305040 is about 371.5808668222.

Adding to 51305040 its reverse (4050315), we get a palindrome (55355355).

The spelling of 51305040 in words is "fifty-one million, three hundred five thousand, forty".