43609661 has 2 divisors, whose sum is σ = 43609662. Its totient is φ = 43609660.

The previous prime is 43609637. The next prime is 43609663. The reversal of 43609661 is 16690634.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22033636 + 21576025 = 4694^2 + 4645^2 .

It is a cyclic number.

It is not a de Polignac number, because 43609661 - 2²² = 39415357 is a prime.

Together with 43609663, 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 (43609663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21804830 + 21804831.

It is an arithmetic number, because the mean of its divisors is an integer number (21804831).

Almost surely, 2^43609661 is an apocalyptic number.

It is an amenable number.

43609661 is a deficient number, since it is larger than the sum of its proper divisors (1).

43609661 is an equidigital number, since it uses as much as digits as its factorization.

43609661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 35.

The square root of 43609661 is about 6603.7611252982. The cubic root of 43609661 is about 351.9877669862.

The spelling of 43609661 in words is "forty-three million, six hundred nine thousand, six hundred sixty-one".