1020643 has 4 divisors (see below), whose sum is σ = 1099168. Its totient is φ = 942120.

The previous prime is 1020631. The next prime is 1020667. The reversal of 1020643 is 3460201.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1020643 is a prime.

It is a Duffinian number.

1020643 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1020683) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39243 + ... + 39268.

It is an arithmetic number, because the mean of its divisors is an integer number (274792).

2^1020643 is an apocalyptic number.

1020643 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

1020643 is a deficient number, since it is larger than the sum of its proper divisors (78525).

1020643 is an equidigital number, since it uses as much as digits as its factorization.

1020643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78524.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 1020643 is about 1010.2687761185. The cubic root of 1020643 is about 100.6834187482.

Adding to 1020643 its reverse (3460201), we get a palindrome (4480844).

The spelling of 1020643 in words is "one million, twenty thousand, six hundred forty-three".