664451 has 4 divisors (see below), whose sum is σ = 668304. Its totient is φ = 660600.

The previous prime is 664441. The next prime is 664459. The reversal of 664451 is 154466.

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 664451 - 2¹⁸ = 402307 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 664451.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 664451.

It is not an unprimeable number, because it can be changed into a prime (664459) 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, 1655 + ... + 2016.

It is an arithmetic number, because the mean of its divisors is an integer number (167076).

2⁶⁶⁴⁴⁵¹ is an apocalyptic number.

664451 is a deficient number, since it is larger than the sum of its proper divisors (3853).

664451 is a wasteful number, since it uses less digits than its factorization.

664451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3852.

The product of its digits is 2880, while the sum is 26.

The square root of 664451 is about 815.1386385149. The cubic root of 664451 is about 87.2611609053.

The spelling of 664451 in words is "six hundred sixty-four thousand, four hundred fifty-one".