661607 has 2 divisors, whose sum is σ = 661608. Its totient is φ = 661606.

The previous prime is 661603. The next prime is 661613. The reversal of 661607 is 706166.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 661607 - 2² = 661603 is a prime.

It is a Chen prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330803 + 330804.

It is an arithmetic number, because the mean of its divisors is an integer number (330804).

2⁶⁶¹⁶⁰⁷ is an apocalyptic number.

661607 is a deficient number, since it is larger than the sum of its proper divisors (1).

661607 is an equidigital number, since it uses as much as digits as its factorization.

661607 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 661607 is about 813.3922792847. The cubic root of 661607 is about 87.1364837099.

The spelling of 661607 in words is "six hundred sixty-one thousand, six hundred seven".