661849 has 2 divisors, whose sum is σ = 661850. Its totient is φ = 661848.

The previous prime is 661823. The next prime is 661873. The reversal of 661849 is 948166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 535824 + 126025 = 732^2 + 355^2 .

It is a cyclic number.

It is not a de Polignac number, because 661849 - 2⁷ = 661721 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661879) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330924 + 330925.

It is an arithmetic number, because the mean of its divisors is an integer number (330925).

2⁶⁶¹⁸⁴⁹ is an apocalyptic number.

It is an amenable number.

661849 is a deficient number, since it is larger than the sum of its proper divisors (1).

661849 is an equidigital number, since it uses as much as digits as its factorization.

661849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10368, while the sum is 34.

The square root of 661849 is about 813.5410253945. The cubic root of 661849 is about 87.1471065613.

The spelling of 661849 in words is "six hundred sixty-one thousand, eight hundred forty-nine".