1645642 has 4 divisors (see below), whose sum is σ = 2468466. Its totient is φ = 822820.

The previous prime is 1645613. The next prime is 1645643. The reversal of 1645642 is 2465461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 2465461 = 31 ⋅79531.

It can be written as a sum of positive squares in only one way, i.e., 1635841 + 9801 = 1279^2 + 99^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1645642.

It is not an unprimeable number, because it can be changed into a prime (1645643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 411409 + ... + 411412.

2^1645642 is an apocalyptic number.

1645642 is a deficient number, since it is larger than the sum of its proper divisors (822824).

1645642 is an equidigital number, since it uses as much as digits as its factorization.

1645642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 822823.

The product of its digits is 5760, while the sum is 28.

The square root of 1645642 is about 1282.8257870810. The cubic root of 1645642 is about 118.0624489898.

The spelling of 1645642 in words is "one million, six hundred forty-five thousand, six hundred forty-two".