51999985 has 8 divisors (see below), whose sum is σ = 64086696. Its totient is φ = 40475520.

The previous prime is 51999971. The next prime is 52000007. The reversal of 51999985 is 58999915.

It can be written as a sum of positive squares in 4 ways, for example, as 14447601 + 37552384 = 3801^2 + 6128^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 51999985 - 2¹¹ = 51997937 is a prime.

It is a Duffinian number.

It is a zygodrome in base 9.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 140356 + ... + 140725.

It is an arithmetic number, because the mean of its divisors is an integer number (8010837).

Almost surely, 2^51999985 is an apocalyptic number.

It is an amenable number.

51999985 is a deficient number, since it is larger than the sum of its proper divisors (12086711).

51999985 is a wasteful number, since it uses less digits than its factorization.

51999985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281123.

The product of its digits is 1312200, while the sum is 55.

The square root of 51999985 is about 7211.1015108650. The cubic root of 51999985 is about 373.2510797922.

The spelling of 51999985 in words is "fifty-one million, nine hundred ninety-nine thousand, nine hundred eighty-five".