51087985 has 16 divisors (see below), whose sum is σ = 66514896. Its totient is φ = 37444608.

The previous prime is 51087983. The next prime is 51087989. The reversal of 51087985 is 58978015.

It can be written as a sum of positive squares in 8 ways, for example, as 14799409 + 36288576 = 3847^2 + 6024^2 .

It is a cyclic number.

It is not a de Polignac number, because 51087985 - 2¹ = 51087983 is a prime.

It is a super-2 number, since 2×51087985² = 5219964422720450, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51087983) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6037 + ... + 11773.

It is an arithmetic number, because the mean of its divisors is an integer number (4157181).

Almost surely, 2^51087985 is an apocalyptic number.

It is an amenable number.

51087985 is a deficient number, since it is larger than the sum of its proper divisors (15426911).

51087985 is a wasteful number, since it uses less digits than its factorization.

51087985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5892.

The product of its (nonzero) digits is 100800, while the sum is 43.

The square root of 51087985 is about 7147.5859561113. The cubic root of 51087985 is about 371.0561133560.

The spelling of 51087985 in words is "fifty-one million, eighty-seven thousand, nine hundred eighty-five".