661139 has 2 divisors, whose sum is σ = 661140. Its totient is φ = 661138.

The previous prime is 661121. The next prime is 661183. The reversal of 661139 is 931166.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661139 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (661109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330569 + 330570.

It is an arithmetic number, because the mean of its divisors is an integer number (330570).

2⁶⁶¹¹³⁹ is an apocalyptic number.

661139 is a deficient number, since it is larger than the sum of its proper divisors (1).

661139 is an equidigital number, since it uses as much as digits as its factorization.

661139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 972, while the sum is 26.

The square root of 661139 is about 813.1045443238. The cubic root of 661139 is about 87.1159329934.

The spelling of 661139 in words is "six hundred sixty-one thousand, one hundred thirty-nine".