51661723 has 4 divisors (see below), whose sum is σ = 51698088. Its totient is φ = 51625360.

The previous prime is 51661699. The next prime is 51661733. The reversal of 51661723 is 32716615.

51661723 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 an emirpimes, since its reverse is a distinct semiprime: 32716615 = 5 ⋅6543323.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51661723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51661733) 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, 15961 + ... + 18922.

It is an arithmetic number, because the mean of its divisors is an integer number (12924522).

Almost surely, 2^51661723 is an apocalyptic number.

51661723 is a deficient number, since it is larger than the sum of its proper divisors (36365).

51661723 is a wasteful number, since it uses less digits than its factorization.

51661723 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36364.

The product of its digits is 7560, while the sum is 31.

The square root of 51661723 is about 7187.6089904780. The cubic root of 51661723 is about 372.4399807207.

It can be divided in two parts, 5166 and 1723, that added together give a square (6889 = 83²).

The spelling of 51661723 in words is "fifty-one million, six hundred sixty-one thousand, seven hundred twenty-three".