1001639 has 2 divisors, whose sum is σ = 1001640. Its totient is φ = 1001638.

The previous prime is 1001629. The next prime is 1001659. The reversal of 1001639 is 9361001.

It is an a-pointer prime, because the next prime (1001659) can be obtained adding 1001639 to its sum of digits (20).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1001639 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1001639.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1001629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500819 + 500820.

It is an arithmetic number, because the mean of its divisors is an integer number (500820).

2^1001639 is an apocalyptic number.

1001639 is a deficient number, since it is larger than the sum of its proper divisors (1).

1001639 is an equidigital number, since it uses as much as digits as its factorization.

1001639 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 162, while the sum is 20.

The square root of 1001639 is about 1000.8191644848. The cubic root of 1001639 is about 100.0546035125.

The spelling of 1001639 in words is "one million, one thousand, six hundred thirty-nine".