661394 has 4 divisors (see below), whose sum is σ = 992094. Its totient is φ = 330696.

The previous prime is 661393. The next prime is 661417. The reversal of 661394 is 493166.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 619369 + 42025 = 787^2 + 205^2 .

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 661394.

It is not an unprimeable number, because it can be changed into a prime (661393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165347 + ... + 165350.

2⁶⁶¹³⁹⁴ is an apocalyptic number.

661394 is a deficient number, since it is larger than the sum of its proper divisors (330700).

661394 is a wasteful number, since it uses less digits than its factorization.

661394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330699.

The product of its digits is 3888, while the sum is 29.

The square root of 661394 is about 813.2613356111. The cubic root of 661394 is about 87.1271317013.

The spelling of 661394 in words is "six hundred sixty-one thousand, three hundred ninety-four".