51666423 has 4 divisors (see below), whose sum is σ = 68888568. Its totient is φ = 34444280.

The previous prime is 51666413. The next prime is 51666443. The reversal of 51666423 is 32466615.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51666423 - 2¹⁰ = 51665399 is a prime.

It is a super-2 number, since 2×51666423² = 5338838531229858, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51666403) 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, 8611068 + ... + 8611073.

It is an arithmetic number, because the mean of its divisors is an integer number (17222142).

Almost surely, 2^51666423 is an apocalyptic number.

51666423 is a deficient number, since it is larger than the sum of its proper divisors (17222145).

51666423 is a wasteful number, since it uses less digits than its factorization.

51666423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17222144.

The product of its digits is 25920, while the sum is 33.

The square root of 51666423 is about 7187.9359346060. The cubic root of 51666423 is about 372.4512748003.

The spelling of 51666423 in words is "fifty-one million, six hundred sixty-six thousand, four hundred twenty-three".