1645729 has 2 divisors, whose sum is σ = 1645730. Its totient is φ = 1645728.

The previous prime is 1645727. The next prime is 1645733. The reversal of 1645729 is 9275461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 883600 + 762129 = 940^2 + 873^2 .

It is a cyclic number.

It is not a de Polignac number, because 1645729 - 2¹ = 1645727 is a prime.

Together with 1645727, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 1645694 and 1645703.

It is not a weakly prime, because it can be changed into another prime (1645727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822864 + 822865.

It is an arithmetic number, because the mean of its divisors is an integer number (822865).

2^1645729 is an apocalyptic number.

It is an amenable number.

1645729 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645729 is an equidigital number, since it uses as much as digits as its factorization.

1645729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15120, while the sum is 34.

The square root of 1645729 is about 1282.8596961476. The cubic root of 1645729 is about 118.0645294852.

The spelling of 1645729 in words is "one million, six hundred forty-five thousand, seven hundred twenty-nine".