1909081 has 2 divisors, whose sum is σ = 1909082.
Its totient is φ = 1909080.
The previous prime is 1909079. The next prime is 1909087. The reversal of 1909081 is 1809091.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 1243225 + 665856 = 1115^2 + 816^2
It is an emirp because it is prime and its reverse (1809091) is a distict prime.
It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 1806061 and 1606081.
It is a cyclic number.
It is not a de Polignac number, because 1909081 - 21 = 1909079 is a prime.
It is a super-2 number, since 2×19090812 = 7289180529122, which contains 22 as substring.
Together with 1909079, it forms a pair of twin primes.
It is not a weakly prime, because it can be changed into another prime (1909087) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 954540 + 954541.
It is an arithmetic number, because the mean of its divisors is an integer number (954541).
21909081 is an apocalyptic number.
It is an amenable number.
1909081 is a deficient number, since it is larger than the sum of its proper divisors (1).
1909081 is an equidigital number, since it uses as much as digits as its factorization.
1909081 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 648, while the sum is 28.
The square root of 1909081 is about 1381.6949735741.
The cubic root of 1909081 is about 124.0532419645.
The spelling of 1909081 in words is "one million, nine hundred nine thousand, eighty-one".