661243 has 8 divisors (see below), whose sum is σ = 737280. Its totient is φ = 587880.

The previous prime is 661237. The next prime is 661253. The reversal of 661243 is 342166.

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 661243 - 2⁹ = 660731 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661253) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 123 + ... + 1156.

It is an arithmetic number, because the mean of its divisors is an integer number (92160).

2⁶⁶¹²⁴³ is an apocalyptic number.

661243 is a deficient number, since it is larger than the sum of its proper divisors (76037).

661243 is a wasteful number, since it uses less digits than its factorization.

661243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1337.

The product of its digits is 864, while the sum is 22.

The square root of 661243 is about 813.1684942249. The cubic root of 661243 is about 87.1205006572.

The spelling of 661243 in words is "six hundred sixty-one thousand, two hundred forty-three".