664723523 has 4 divisors (see below), whose sum is σ = 664795560. Its totient is φ = 664651488.

The previous prime is 664723519. The next prime is 664723601. The reversal of 664723523 is 325327466.

It is a happy number.

664723523 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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 325327466 = 2 ⋅162663733.

It is a cyclic number.

It is not a de Polignac number, because 664723523 - 2² = 664723519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664723223) 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, 19718 + ... + 41451.

It is an arithmetic number, because the mean of its divisors is an integer number (166198890).

Almost surely, 2^664723523 is an apocalyptic number.

664723523 is a deficient number, since it is larger than the sum of its proper divisors (72037).

664723523 is a wasteful number, since it uses less digits than its factorization.

664723523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72036.

The product of its digits is 181440, while the sum is 38.

The square root of 664723523 is about 25782.2327000592. The cubic root of 664723523 is about 872.7308926068.

The spelling of 664723523 in words is "six hundred sixty-four million, seven hundred twenty-three thousand, five hundred twenty-three".