1645901 has 2 divisors, whose sum is σ = 1645902. Its totient is φ = 1645900.

The previous prime is 1645879. The next prime is 1645907. The reversal of 1645901 is 1095461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 948676 + 697225 = 974^2 + 835^2 .

It is an emirp because it is prime and its reverse (1095461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1645901 - 2¹⁸ = 1383757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1645907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822950 + 822951.

It is an arithmetic number, because the mean of its divisors is an integer number (822951).

2^1645901 is an apocalyptic number.

It is an amenable number.

1645901 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645901 is an equidigital number, since it uses as much as digits as its factorization.

1645901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 1645901 is about 1282.9267321246. The cubic root of 1645901 is about 118.0686424329.

The spelling of 1645901 in words is "one million, six hundred forty-five thousand, nine hundred one".