66814219 has 4 divisors (see below), whose sum is σ = 66981240. Its totient is φ = 66647200.

The previous prime is 66814201. The next prime is 66814229. The reversal of 66814219 is 91241866.

It is a happy number.

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 66814219 - 2⁹ = 66813707 is a prime.

It is a super-2 number, since 2×66814219² = 8928279721159922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66814229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 82909 + ... + 83710.

It is an arithmetic number, because the mean of its divisors is an integer number (16745310).

Almost surely, 2^66814219 is an apocalyptic number.

66814219 is a deficient number, since it is larger than the sum of its proper divisors (167021).

66814219 is a wasteful number, since it uses less digits than its factorization.

66814219 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167020.

The product of its digits is 20736, while the sum is 37.

The square root of 66814219 is about 8173.9965133342. The cubic root of 66814219 is about 405.7790603082.

The spelling of 66814219 in words is "sixty-six million, eight hundred fourteen thousand, two hundred nineteen".