1806557 has 2 divisors, whose sum is σ = 1806558.
Its totient is φ = 1806556.
The previous prime is 1806551. The next prime is 1806569. The reversal of 1806557 is 7556081.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 1666681 + 139876 = 1291^2 + 374^2
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-1806557 is a prime.
It is a Chen prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (1806551) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 903278 + 903279.
It is an arithmetic number, because the mean of its divisors is an integer number (903279).
21806557 is an apocalyptic number.
It is an amenable number.
1806557 is a deficient number, since it is larger than the sum of its proper divisors (1).
1806557 is an equidigital number, since it uses as much as digits as its factorization.
1806557 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 8400, while the sum is 32.
The square root of 1806557 is about 1344.0822147473.
The cubic root of 1806557 is about 121.7915683203.
The spelling of 1806557 in words is "one million, eight hundred six thousand, five hundred fifty-seven".