661373 has 2 divisors, whose sum is σ = 661374. Its totient is φ = 661372.

The previous prime is 661361. The next prime is 661393. The reversal of 661373 is 373166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 465124 + 196249 = 682^2 + 443^2 .

It is a cyclic number.

It is not a de Polignac number, because 661373 - 2⁸ = 661117 is a prime.

It is a Sophie Germain prime.

It is an Ulam number.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661343) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330686 + 330687.

It is an arithmetic number, because the mean of its divisors is an integer number (330687).

2⁶⁶¹³⁷³ is an apocalyptic number.

It is an amenable number.

661373 is a deficient number, since it is larger than the sum of its proper divisors (1).

661373 is an equidigital number, since it uses as much as digits as its factorization.

661373 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2268, while the sum is 26.

The square root of 661373 is about 813.2484245297. The cubic root of 661373 is about 87.1262095635.

The spelling of 661373 in words is "six hundred sixty-one thousand, three hundred seventy-three".