661447 has 8 divisors (see below), whose sum is σ = 719360. Its totient is φ = 605880.

The previous prime is 661439. The next prime is 661459. The reversal of 661447 is 744166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 661447 - 2³ = 661439 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28 + ... + 1150.

It is an arithmetic number, because the mean of its divisors is an integer number (89920).

2⁶⁶¹⁴⁴⁷ is an apocalyptic number.

661447 is a deficient number, since it is larger than the sum of its proper divisors (57913).

661447 is a wasteful number, since it uses less digits than its factorization.

661447 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1173.

The product of its digits is 4032, while the sum is 28.

The square root of 661447 is about 813.2939198101. The cubic root of 661447 is about 87.1294589145.

The spelling of 661447 in words is "six hundred sixty-one thousand, four hundred forty-seven".