1021663 has 2 divisors, whose sum is σ = 1021664. Its totient is φ = 1021662.

The previous prime is 1021661. The next prime is 1021673. The reversal of 1021663 is 3661201.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1021663 - 2¹ = 1021661 is a prime.

Together with 1021661, it forms a pair of twin primes.

1021663 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 1021663.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1021661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510831 + 510832.

It is an arithmetic number, because the mean of its divisors is an integer number (510832).

2^1021663 is an apocalyptic number.

1021663 is a deficient number, since it is larger than the sum of its proper divisors (1).

1021663 is an equidigital number, since it uses as much as digits as its factorization.

1021663 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 1021663 is about 1010.7734662129. The cubic root of 1021663 is about 100.7169475777.

Adding to 1021663 its reverse (3661201), we get a palindrome (4682864).

The spelling of 1021663 in words is "one million, twenty-one thousand, six hundred sixty-three".