51491723 has 4 divisors (see below), whose sum is σ = 51506088. Its totient is φ = 51477360.

The previous prime is 51491707. The next prime is 51491731. The reversal of 51491723 is 32719415.

51491723 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 is a cyclic number.

It is not a de Polignac number, because 51491723 - 2⁴ = 51491707 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 51491723.

It is not an unprimeable number, because it can be changed into a prime (51491773) 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, 3143 + ... + 10623.

It is an arithmetic number, because the mean of its divisors is an integer number (12876522).

Almost surely, 2^51491723 is an apocalyptic number.

51491723 is a deficient number, since it is larger than the sum of its proper divisors (14365).

51491723 is an equidigital number, since it uses as much as digits as its factorization.

51491723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14364.

The product of its digits is 7560, while the sum is 32.

The square root of 51491723 is about 7175.7733381149. The cubic root of 51491723 is about 372.0310101524.

The spelling of 51491723 in words is "fifty-one million, four hundred ninety-one thousand, seven hundred twenty-three".