664304551 has 4 divisors (see below), whose sum is σ = 664650504. Its totient is φ = 663958600.

The previous prime is 664304539. The next prime is 664304569. The reversal of 664304551 is 155403466.

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 664304551 - 2¹⁹ = 663780263 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 (664304521) 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, 170080 + ... + 173941.

It is an arithmetic number, because the mean of its divisors is an integer number (166162626).

Almost surely, 2^664304551 is an apocalyptic number.

664304551 is a deficient number, since it is larger than the sum of its proper divisors (345953).

664304551 is a wasteful number, since it uses less digits than its factorization.

664304551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 345952.

The product of its (nonzero) digits is 43200, while the sum is 34.

The square root of 664304551 is about 25774.1062114674. The cubic root of 664304551 is about 872.5474947258.

The spelling of 664304551 in words is "six hundred sixty-four million, three hundred four thousand, five hundred fifty-one".