51999869 has 4 divisors (see below), whose sum is σ = 52086144. Its totient is φ = 51913596.

The previous prime is 51999853. The next prime is 51999887. The reversal of 51999869 is 96899915.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51999869 - 2⁴ = 51999853 is a prime.

It is a super-2 number, since 2×51999869² = 5407972752034322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51999569) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42227 + ... + 43440.

It is an arithmetic number, because the mean of its divisors is an integer number (13021536).

Almost surely, 2^51999869 is an apocalyptic number.

It is an amenable number.

51999869 is a deficient number, since it is larger than the sum of its proper divisors (86275).

51999869 is an equidigital number, since it uses as much as digits as its factorization.

51999869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86274.

The product of its digits is 1574640, while the sum is 56.

The square root of 51999869 is about 7211.0934677065. The cubic root of 51999869 is about 373.2508022462.

The spelling of 51999869 in words is "fifty-one million, nine hundred ninety-nine thousand, eight hundred sixty-nine".