1051991 has 2 divisors, whose sum is σ = 1051992. Its totient is φ = 1051990.

The previous prime is 1051987. The next prime is 1052027. The reversal of 1051991 is 1991501.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1051991 - 2² = 1051987 is a prime.

It is a super-2 number, since 2×1051991² = 2213370128162, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1051991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1051961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 525995 + 525996.

It is an arithmetic number, because the mean of its divisors is an integer number (525996).

2^1051991 is an apocalyptic number.

1051991 is a deficient number, since it is larger than the sum of its proper divisors (1).

1051991 is an equidigital number, since it uses as much as digits as its factorization.

1051991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 405, while the sum is 26.

The square root of 1051991 is about 1025.6661250134. Note that the first 3 decimals coincide. The cubic root of 1051991 is about 101.7038378218.

The spelling of 1051991 in words is "one million, fifty-one thousand, nine hundred ninety-one".