661224 has 16 divisors (see below), whose sum is σ = 1653120. Its totient is φ = 220400.

The previous prime is 661217. The next prime is 661231. The reversal of 661224 is 422166.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (661217) and next prime (661231).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 661224.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13752 + ... + 13799.

It is an arithmetic number, because the mean of its divisors is an integer number (103320).

2⁶⁶¹²²⁴ is an apocalyptic number.

It is an amenable number.

661224 is an abundant number, since it is smaller than the sum of its proper divisors (991896).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661224 is a wasteful number, since it uses less digits than its factorization.

661224 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27560 (or 27556 counting only the distinct ones).

The product of its digits is 576, while the sum is 21.

The square root of 661224 is about 813.1568114454. The cubic root of 661224 is about 87.1196662159.

The spelling of 661224 in words is "six hundred sixty-one thousand, two hundred twenty-four".