51809957 has 4 divisors (see below), whose sum is σ = 51825036. Its totient is φ = 51794880.

The previous prime is 51809929. The next prime is 51809971. The reversal of 51809957 is 75990815.

It is a happy number.

51809957 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 brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 32878756 + 18931201 = 5734^2 + 4351^2 .

It is a cyclic number.

It is not a de Polignac number, because 51809957 - 2⁶ = 51809893 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 (51809917) 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, 407 + ... + 10187.

It is an arithmetic number, because the mean of its divisors is an integer number (12956259).

Almost surely, 2^51809957 is an apocalyptic number.

It is an amenable number.

51809957 is a deficient number, since it is larger than the sum of its proper divisors (15079).

51809957 is an equidigital number, since it uses as much as digits as its factorization.

51809957 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15078.

The product of its (nonzero) digits is 113400, while the sum is 44.

The square root of 51809957 is about 7197.9133781951. The cubic root of 51809957 is about 372.7958570221.

The spelling of 51809957 in words is "fifty-one million, eight hundred nine thousand, nine hundred fifty-seven".