1908106661 has 2 divisors, whose sum is σ = 1908106662. Its totient is φ = 1908106660.

The previous prime is 1908106643. The next prime is 1908106663. The reversal of 1908106661 is 1666018091.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1420536100 + 487570561 = 37690^2 + 22081^2 .

It is an emirp because it is prime and its reverse (1666018091) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1999018061 and 1608109991.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1908106661 is a prime.

Together with 1908106663, 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 (1908106663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 954053330 + 954053331.

It is an arithmetic number, because the mean of its divisors is an integer number (954053331).

Almost surely, 2^1908106661 is an apocalyptic number.

It is an amenable number.

1908106661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1908106661 is an equidigital number, since it uses as much as digits as its factorization.

1908106661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 1908106661 is about 43681.8802365466. The cubic root of 1908106661 is about 1240.3213399328.

The spelling of 1908106661 in words is "one billion, nine hundred eight million, one hundred six thousand, six hundred sixty-one".