51665213 has 4 divisors (see below), whose sum is σ = 51724608. Its totient is φ = 51605820.

The previous prime is 51665203. The next prime is 51665219. The reversal of 51665213 is 31256615.

51665213 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 51665213 - 2⁴ = 51665197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51665219) 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 3 ways as a sum of consecutive naturals, for example, 28373 + ... + 30138.

It is an arithmetic number, because the mean of its divisors is an integer number (12931152).

Almost surely, 2^51665213 is an apocalyptic number.

It is an amenable number.

51665213 is a deficient number, since it is larger than the sum of its proper divisors (59395).

51665213 is an equidigital number, since it uses as much as digits as its factorization.

51665213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59394.

The product of its digits is 5400, while the sum is 29.

The square root of 51665213 is about 7187.8517653051. The cubic root of 51665213 is about 372.4483672410.

The spelling of 51665213 in words is "fifty-one million, six hundred sixty-five thousand, two hundred thirteen".