1091997 has 6 divisors (see below), whose sum is σ = 1577342. Its totient is φ = 727992.

The previous prime is 1091983. The next prime is 1092019. The reversal of 1091997 is 7991901.

It can be written as a sum of positive squares in only one way, i.e., 793881 + 298116 = 891^2 + 546^2 .

It is not a de Polignac number, because 1091997 - 2⁷ = 1091869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1091917) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 60658 + ... + 60675.

2^1091997 is an apocalyptic number.

It is an amenable number.

1091997 is a deficient number, since it is larger than the sum of its proper divisors (485345).

1091997 is a wasteful number, since it uses less digits than its factorization.

1091997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121339 (or 121336 counting only the distinct ones).

The product of its (nonzero) digits is 5103, while the sum is 36.

The square root of 1091997 is about 1044.9866027849. The cubic root of 1091997 is about 102.9770583900.

The spelling of 1091997 in words is "one million, ninety-one thousand, nine hundred ninety-seven".