1008991 has 2 divisors, whose sum is σ = 1008992. Its totient is φ = 1008990.

The previous prime is 1008989. The next prime is 1009007. The reversal of 1008991 is 1998001.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1008991 - 2¹ = 1008989 is a prime.

Together with 1008989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1008901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 504495 + 504496.

It is an arithmetic number, because the mean of its divisors is an integer number (504496).

2^1008991 is an apocalyptic number.

1008991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1008991 is an equidigital number, since it uses as much as digits as its factorization.

1008991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 648, while the sum is 28.

The square root of 1008991 is about 1004.4854404122. The cubic root of 1008991 is about 100.2988062589.

The spelling of 1008991 in words is "one million, eight thousand, nine hundred ninety-one".