991697 has 4 divisors (see below), whose sum is σ = 1133376. Its totient is φ = 850020.

The previous prime is 991693. The next prime is 991703. The reversal of 991697 is 796199.

It is a happy number.

991697 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 796199 = 199 ⋅4001.

It is a cyclic number.

It is not a de Polignac number, because 991697 - 2² = 991693 is a prime.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 991697.

It is not an unprimeable number, because it can be changed into a prime (991693) 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, 70829 + ... + 70842.

It is an arithmetic number, because the mean of its divisors is an integer number (283344).

2⁹⁹¹⁶⁹⁷ is an apocalyptic number.

It is an amenable number.

991697 is a deficient number, since it is larger than the sum of its proper divisors (141679).

991697 is a wasteful number, since it uses less digits than its factorization.

991697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141678.

The product of its digits is 30618, while the sum is 41.

The square root of 991697 is about 995.8398465617. The cubic root of 991697 is about 99.7224637824.

The spelling of 991697 in words is "nine hundred ninety-one thousand, six hundred ninety-seven".