51666807 has 4 divisors (see below), whose sum is σ = 68889080. Its totient is φ = 34444536.

The previous prime is 51666787. The next prime is 51666821. The reversal of 51666807 is 70866615.

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

It is not a de Polignac number, because 51666807 - 2¹⁶ = 51601271 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 (51666827) 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, 8611132 + ... + 8611137.

It is an arithmetic number, because the mean of its divisors is an integer number (17222270).

Almost surely, 2^51666807 is an apocalyptic number.

51666807 is a deficient number, since it is larger than the sum of its proper divisors (17222273).

51666807 is a wasteful number, since it uses less digits than its factorization.

51666807 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17222272.

The product of its (nonzero) digits is 60480, while the sum is 39.

The square root of 51666807 is about 7187.9626459797. The cubic root of 51666807 is about 372.4521975203.

The spelling of 51666807 in words is "fifty-one million, six hundred sixty-six thousand, eight hundred seven".