664420447 has 4 divisors (see below), whose sum is σ = 664631856. Its totient is φ = 664209040.

The previous prime is 664420423. The next prime is 664420453. The reversal of 664420447 is 744024466.

664420447 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 664420447 - 2¹⁵ = 664387679 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 (664420487) 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, 100918 + ... + 107299.

It is an arithmetic number, because the mean of its divisors is an integer number (166157964).

Almost surely, 2^664420447 is an apocalyptic number.

664420447 is a deficient number, since it is larger than the sum of its proper divisors (211409).

664420447 is a wasteful number, since it uses less digits than its factorization.

664420447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211408.

The product of its (nonzero) digits is 129024, while the sum is 37.

The square root of 664420447 is about 25776.3544164026. The cubic root of 664420447 is about 872.5982339457.

The spelling of 664420447 in words is "six hundred sixty-four million, four hundred twenty thousand, four hundred forty-seven".