1661109101 has 2 divisors, whose sum is σ = 1661109102. Its totient is φ = 1661109100.

The previous prime is 1661109089. The next prime is 1661109103. The reversal of 1661109101 is 1019011661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 981255625 + 679853476 = 31325^2 + 26074^2 .

It is an emirp because it is prime and its reverse (1019011661) is a distict prime. It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1016011991 and 1991106101.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1661109101 is a prime.

Together with 1661109103, 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 (1661109103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830554550 + 830554551.

It is an arithmetic number, because the mean of its divisors is an integer number (830554551).

Almost surely, 2^1661109101 is an apocalyptic number.

It is an amenable number.

1661109101 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661109101 is an equidigital number, since it uses as much as digits as its factorization.

1661109101 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 26.

The square root of 1661109101 is about 40756.7062089173. The cubic root of 1661109101 is about 1184.3117894349.

The spelling of 1661109101 in words is "one billion, six hundred sixty-one million, one hundred nine thousand, one hundred one".