66376621 has 4 divisors (see below), whose sum is σ = 68665500. Its totient is φ = 64087744.

The previous prime is 66376603. The next prime is 66376627. The reversal of 66376621 is 12667366.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12667366 = 2 ⋅6333683.

It can be written as a sum of positive squares in 2 ways, for example, as 49154121 + 17222500 = 7011^2 + 4150^2 .

It is a cyclic number.

It is not a de Polignac number, because 66376621 - 2²³ = 57988013 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 (66376627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1144396 + ... + 1144453.

It is an arithmetic number, because the mean of its divisors is an integer number (17166375).

Almost surely, 2^66376621 is an apocalyptic number.

It is an amenable number.

66376621 is a deficient number, since it is larger than the sum of its proper divisors (2288879).

66376621 is a wasteful number, since it uses less digits than its factorization.

66376621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2288878.

The product of its digits is 54432, while the sum is 37.

The square root of 66376621 is about 8147.1848512232. The cubic root of 66376621 is about 404.8912394030.

It can be divided in two parts, 663 and 76621, that added together give a square (77284 = 278²).

The spelling of 66376621 in words is "sixty-six million, three hundred seventy-six thousand, six hundred twenty-one".