669961 has 4 divisors (see below), whose sum is σ = 671872. Its totient is φ = 668052.

The previous prime is 669947. The next prime is 669971. The reversal of 669961 is 169966.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 669961 - 2¹³ = 661769 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 669961.

It is not an unprimeable number, because it can be changed into a prime (669901) 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, 261 + ... + 1186.

It is an arithmetic number, because the mean of its divisors is an integer number (167968).

2⁶⁶⁹⁹⁶¹ is an apocalyptic number.

It is an amenable number.

669961 is a deficient number, since it is larger than the sum of its proper divisors (1911).

669961 is a wasteful number, since it uses less digits than its factorization.

669961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1910.

The product of its digits is 17496, while the sum is 37.

The square root of 669961 is about 818.5114537989. The cubic root of 669961 is about 87.5017033682.

The spelling of 669961 in words is "six hundred sixty-nine thousand, nine hundred sixty-one".