51187509 has 6 divisors (see below), whose sum is σ = 73937526. Its totient is φ = 34125000.

The previous prime is 51187483. The next prime is 51187529. The reversal of 51187509 is 90578115.

51187509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 31606884 + 19580625 = 5622^2 + 4425^2 .

It is not a de Polignac number, because 51187509 - 2²³ = 42798901 is a prime.

It is a super-2 number, since 2×51187509² = 5240322155250162, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51187529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2843742 + ... + 2843759.

It is an arithmetic number, because the mean of its divisors is an integer number (12322921).

Almost surely, 2^51187509 is an apocalyptic number.

It is an amenable number.

51187509 is a deficient number, since it is larger than the sum of its proper divisors (22750017).

51187509 is a wasteful number, since it uses less digits than its factorization.

51187509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5687507 (or 5687504 counting only the distinct ones).

The product of its (nonzero) digits is 12600, while the sum is 36.

The square root of 51187509 is about 7154.5446395980. The cubic root of 51187509 is about 371.2969073132.

The spelling of 51187509 in words is "fifty-one million, one hundred eighty-seven thousand, five hundred nine".