1645601 has 2 divisors, whose sum is σ = 1645602. Its totient is φ = 1645600.

The previous prime is 1645561. The next prime is 1645603. The reversal of 1645601 is 1065461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1081600 + 564001 = 1040^2 + 751^2 .

It is a cyclic number.

It is not a de Polignac number, because 1645601 - 2⁶ = 1645537 is a prime.

Together with 1645603, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 15.

It is not a weakly prime, because it can be changed into another prime (1645603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822800 + 822801.

It is an arithmetic number, because the mean of its divisors is an integer number (822801).

2^1645601 is an apocalyptic number.

It is an amenable number.

1645601 is a deficient number, since it is larger than the sum of its proper divisors (1).

1645601 is an equidigital number, since it uses as much as digits as its factorization.

1645601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 1645601 is about 1282.8098066354. The cubic root of 1645601 is about 118.0614685010.

The spelling of 1645601 in words is "one million, six hundred forty-five thousand, six hundred one".