661612141 has 2 divisors, whose sum is σ = 661612142. Its totient is φ = 661612140.

The previous prime is 661612139. The next prime is 661612183. The reversal of 661612141 is 141216166.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 473236516 + 188375625 = 21754^2 + 13725^2 .

It is a cyclic number.

It is not a de Polignac number, because 661612141 - 2¹ = 661612139 is a prime.

Together with 661612139, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (661612111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330806070 + 330806071.

It is an arithmetic number, because the mean of its divisors is an integer number (330806071).

Almost surely, 2^661612141 is an apocalyptic number.

It is an amenable number.

661612141 is a deficient number, since it is larger than the sum of its proper divisors (1).

661612141 is an equidigital number, since it uses as much as digits as its factorization.

661612141 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1728, while the sum is 28.

The square root of 661612141 is about 25721.8222721486. The cubic root of 661612141 is about 871.3670940659.

The spelling of 661612141 in words is "six hundred sixty-one million, six hundred twelve thousand, one hundred forty-one".