663394 has 4 divisors (see below), whose sum is σ = 995094. Its totient is φ = 331696.

The previous prime is 663371. The next prime is 663407. The reversal of 663394 is 493366.

663394 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 an emirpimes, since its reverse is a distinct semiprime: 493366 = 2 ⋅246683.

It can be written as a sum of positive squares in only one way, i.e., 582169 + 81225 = 763^2 + 285^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165847 + ... + 165850.

2⁶⁶³³⁹⁴ is an apocalyptic number.

663394 is a deficient number, since it is larger than the sum of its proper divisors (331700).

663394 is a wasteful number, since it uses less digits than its factorization.

663394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 331699.

The product of its digits is 11664, while the sum is 31.

The square root of 663394 is about 814.4900244939. The cubic root of 663394 is about 87.2148650415.

It can be divided in two parts, 66339 and 4, that multiplied together give a triangular number (265356 = T₇₂₈).

The spelling of 663394 in words is "six hundred sixty-three thousand, three hundred ninety-four".