664576421 has 8 divisors (see below), whose sum is σ = 710385984. Its totient is φ = 620176480.

The previous prime is 664576411. The next prime is 664576453. The reversal of 664576421 is 124675466.

It is a happy number.

664576421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664576421 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664576411) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 351431 + ... + 353316.

It is an arithmetic number, because the mean of its divisors is an integer number (88798248).

Almost surely, 2^664576421 is an apocalyptic number.

It is an amenable number.

664576421 is a deficient number, since it is larger than the sum of its proper divisors (45809563).

664576421 is a wasteful number, since it uses less digits than its factorization.

664576421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 704811.

The product of its digits is 241920, while the sum is 41.

The square root of 664576421 is about 25779.3797636793. The cubic root of 664576421 is about 872.6665099843. Note that the first 3 decimals are identical.

The spelling of 664576421 in words is "six hundred sixty-four million, five hundred seventy-six thousand, four hundred twenty-one".