1091731 has 2 divisors, whose sum is σ = 1091732. Its totient is φ = 1091730.

The previous prime is 1091729. The next prime is 1091737. The reversal of 1091731 is 1371901.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1091731 - 2¹ = 1091729 is a prime.

It is a super-2 number, since 2×1091731² = 2383753152722, which contains 22 as substring.

Together with 1091729, it forms a pair of twin primes.

It is a Chen prime.

1091731 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (1091737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 545865 + 545866.

It is an arithmetic number, because the mean of its divisors is an integer number (545866).

2^1091731 is an apocalyptic number.

1091731 is a deficient number, since it is larger than the sum of its proper divisors (1).

1091731 is an equidigital number, since it uses as much as digits as its factorization.

1091731 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 189, while the sum is 22.

The square root of 1091731 is about 1044.8593206743. The cubic root of 1091731 is about 102.9686963030.

The spelling of 1091731 in words is "one million, ninety-one thousand, seven hundred thirty-one".