1345781 has 2 divisors, whose sum is σ = 1345782.
Its totient is φ = 1345780.
The previous prime is 1345777. The next prime is 1345783. The reversal of 1345781 is 1875431.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 1343281 + 2500 = 1159^2 + 50^2
It is an emirp because it is prime and its reverse (1875431) is a distict prime.
It is a cyclic number.
It is not a de Polignac number, because 1345781 - 22 = 1345777 is a prime.
It is a super-2 number, since 2×13457812 = 3622252999922, which contains 22 as substring.
Together with 1345783, 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 (1345783) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 672890 + 672891.
It is an arithmetic number, because the mean of its divisors is an integer number (672891).
21345781 is an apocalyptic number.
It is an amenable number.
1345781 is a deficient number, since it is larger than the sum of its proper divisors (1).
1345781 is an equidigital number, since it uses as much as digits as its factorization.
1345781 is an evil number, because the sum of its binary digits is even.
The product of its digits is 3360, while the sum is 29.
The square root of 1345781 is about 1160.0780146180.
The cubic root of 1345781 is about 110.4056920068.
The spelling of 1345781 in words is "one million, three hundred forty-five thousand, seven hundred eighty-one".