664634 has 4 divisors (see below), whose sum is σ = 996954. Its totient is φ = 332316.

The previous prime is 664633. The next prime is 664661. The reversal of 664634 is 436466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 436466 = 2 ⋅218233.

It can be written as a sum of positive squares in only one way, i.e., 600625 + 64009 = 775^2 + 253^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 664597 and 664606.

It is not an unprimeable number, because it can be changed into a prime (664633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 166157 + ... + 166160.

2⁶⁶⁴⁶³⁴ is an apocalyptic number.

664634 is a deficient number, since it is larger than the sum of its proper divisors (332320).

664634 is a wasteful number, since it uses less digits than its factorization.

664634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332319.

The product of its digits is 10368, while the sum is 29.

The square root of 664634 is about 815.2508816309. The cubic root of 664634 is about 87.2691711909.

The spelling of 664634 in words is "six hundred sixty-four thousand, six hundred thirty-four".