1097981 has 4 divisors (see below), whose sum is σ = 1105500. Its totient is φ = 1090464.

The previous prime is 1097947. The next prime is 1097983. The reversal of 1097981 is 1897901.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1897901 = 71 ⋅26731.

It can be written as a sum of positive squares in 2 ways, for example, as 586756 + 511225 = 766^2 + 715^2 .

It is a cyclic number.

It is not a de Polignac number, because 1097981 - 2¹⁰ = 1096957 is a prime.

It is a super-2 number, since 2×1097981² = 2411124552722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1097983) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3536 + ... + 3833.

It is an arithmetic number, because the mean of its divisors is an integer number (276375).

2^1097981 is an apocalyptic number.

It is an amenable number.

1097981 is a deficient number, since it is larger than the sum of its proper divisors (7519).

1097981 is an equidigital number, since it uses as much as digits as its factorization.

1097981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7518.

The product of its (nonzero) digits is 4536, while the sum is 35.

The square root of 1097981 is about 1047.8458856149. The cubic root of 1097981 is about 103.1648160914.

The spelling of 1097981 in words is "one million, ninety-seven thousand, nine hundred eighty-one".