1021643 has 4 divisors (see below), whose sum is σ = 1167600. Its totient is φ = 875688.

The previous prime is 1021627. The next prime is 1021651. The reversal of 1021643 is 3461201.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1021643 - 2⁴ = 1021627 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1021663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72968 + ... + 72981.

It is an arithmetic number, because the mean of its divisors is an integer number (291900).

2^1021643 is an apocalyptic number.

1021643 is a deficient number, since it is larger than the sum of its proper divisors (145957).

1021643 is an equidigital number, since it uses as much as digits as its factorization.

1021643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145956.

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 1021643 is about 1010.7635727508. The cubic root of 1021643 is about 100.7162903642.

Adding to 1021643 its reverse (3461201), we get a palindrome (4482844).

The spelling of 1021643 in words is "one million, twenty-one thousand, six hundred forty-three".