51666645 has 8 divisors (see below), whose sum is σ = 82666656. Its totient is φ = 27555536.

The previous prime is 51666617. The next prime is 51666649. The reversal of 51666645 is 54666615.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 51666645 - 2⁸ = 51666389 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51666649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1722207 + ... + 1722236.

It is an arithmetic number, because the mean of its divisors is an integer number (10333332).

Almost surely, 2^51666645 is an apocalyptic number.

It is an amenable number.

51666645 is a deficient number, since it is larger than the sum of its proper divisors (31000011).

51666645 is a wasteful number, since it uses less digits than its factorization.

51666645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3444451.

The product of its digits is 129600, while the sum is 39.

The square root of 51666645 is about 7187.9513771310. The cubic root of 51666645 is about 372.4518082483.

It can be divided in two parts, 5166 and 6645, that added together give a palindrome (11811).

The spelling of 51666645 in words is "fifty-one million, six hundred sixty-six thousand, six hundred forty-five".