51061666 has 4 divisors (see below), whose sum is σ = 76592502. Its totient is φ = 25530832.

The previous prime is 51061657. The next prime is 51061667. The reversal of 51061666 is 66616015.

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

It can be written as a sum of positive squares in only one way, i.e., 31036041 + 20025625 = 5571^2 + 4475^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (51061667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12765415 + ... + 12765418.

Almost surely, 2^51061666 is an apocalyptic number.

51061666 is a deficient number, since it is larger than the sum of its proper divisors (25530836).

51061666 is a wasteful number, since it uses less digits than its factorization.

51061666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25530835.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 51061666 is about 7145.7446078068. The cubic root of 51061666 is about 370.9923834115.

The spelling of 51061666 in words is "fifty-one million, sixty-one thousand, six hundred sixty-six".