51015240 has 48 divisors (see below), whose sum is σ = 165800700. Its totient is φ = 13603968.

The previous prime is 51015229. The next prime is 51015241. The reversal of 51015240 is 4251015.

51015240 is a `hidden beast` number, since 510 + 152 + 4 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 48525156 + 2490084 = 6966^2 + 1578^2 .

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

It is not an unprimeable number, because it can be changed into a prime (51015241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 70495 + ... + 71214.

Almost surely, 2^51015240 is an apocalyptic number.

It is an amenable number.

51015240 is an abundant number, since it is smaller than the sum of its proper divisors (114785460).

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

51015240 is a wasteful number, since it uses less digits than its factorization.

51015240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141726 (or 141719 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 51015240 is about 7142.4953622666. The cubic root of 51015240 is about 370.8799121169.

Adding to 51015240 its reverse (4251015), we get a palindrome (55266255).

The spelling of 51015240 in words is "fifty-one million, fifteen thousand, two hundred forty".