664721453 has 8 divisors (see below), whose sum is σ = 737039136. Its totient is φ = 594385200.

The previous prime is 664721419. The next prime is 664721461. The reversal of 664721453 is 354127466.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 664721453 - 2¹⁶ = 664655917 is a prime.

It is a super-2 number, since 2×664721453² = 883709220156862418, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664721753) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 494651 + ... + 495992.

It is an arithmetic number, because the mean of its divisors is an integer number (92129892).

Almost surely, 2^664721453 is an apocalyptic number.

It is an amenable number.

664721453 is a deficient number, since it is larger than the sum of its proper divisors (72317683).

664721453 is a wasteful number, since it uses less digits than its factorization.

664721453 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 990715.

The product of its digits is 120960, while the sum is 38.

The square root of 664721453 is about 25782.1925561035. The cubic root of 664721453 is about 872.7299866889.

The spelling of 664721453 in words is "six hundred sixty-four million, seven hundred twenty-one thousand, four hundred fifty-three".