661199 has 16 divisors (see below), whose sum is σ = 854016. Its totient is φ = 496800.

The previous prime is 661189. The next prime is 661201. The reversal of 661199 is 991166.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 661199 - 2⁴ = 661183 is a prime.

It is an Ulam number.

661199 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

It is a zygodrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661109) 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 15 ways as a sum of consecutive naturals, for example, 2249 + ... + 2525.

It is an arithmetic number, because the mean of its divisors is an integer number (53376).

2⁶⁶¹¹⁹⁹ is an apocalyptic number.

661199 is a deficient number, since it is larger than the sum of its proper divisors (192817).

661199 is a wasteful number, since it uses less digits than its factorization.

661199 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 326.

The product of its digits is 2916, while the sum is 32.

The square root of 661199 is about 813.1414391113. The cubic root of 661199 is about 87.1185682425.

The spelling of 661199 in words is "six hundred sixty-one thousand, one hundred ninety-nine".