66694451 has 4 divisors (see below), whose sum is σ = 70617672. Its totient is φ = 62771232.

The previous prime is 66694447. The next prime is 66694469. The reversal of 66694451 is 15449666.

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

It is a cyclic number.

It is not a de Polignac number, because 66694451 - 2² = 66694447 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66694399 and 66694408.

It is not an unprimeable number, because it can be changed into a prime (66694421) 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, 1961585 + ... + 1961618.

It is an arithmetic number, because the mean of its divisors is an integer number (17654418).

Almost surely, 2^66694451 is an apocalyptic number.

66694451 is a deficient number, since it is larger than the sum of its proper divisors (3923221).

66694451 is a wasteful number, since it uses less digits than its factorization.

66694451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3923220.

The product of its digits is 155520, while the sum is 41.

The square root of 66694451 is about 8166.6670680272. The cubic root of 66694451 is about 405.5364551905.

The spelling of 66694451 in words is "sixty-six million, six hundred ninety-four thousand, four hundred fifty-one".