66688474 has 4 divisors (see below), whose sum is σ = 100032714. Its totient is φ = 33344236.

The previous prime is 66688463. The next prime is 66688481. The reversal of 66688474 is 47488666.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 47488666 = 2 ⋅23744333.

It can be written as a sum of positive squares in only one way, i.e., 62299449 + 4389025 = 7893^2 + 2095^2 .

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 16672117 + ... + 16672120.

Almost surely, 2^66688474 is an apocalyptic number.

66688474 is a deficient number, since it is larger than the sum of its proper divisors (33344240).

66688474 is a wasteful number, since it uses less digits than its factorization.

66688474 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33344239.

The product of its digits is 1548288, while the sum is 49.

The square root of 66688474 is about 8166.3011210707. The cubic root of 66688474 is about 405.5243404205.

The spelling of 66688474 in words is "sixty-six million, six hundred eighty-eight thousand, four hundred seventy-four".