991457 has 4 divisors (see below), whose sum is σ = 1049796. Its totient is φ = 933120.

The previous prime is 991453. The next prime is 991483. The reversal of 991457 is 754199.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 754199 = 31 ⋅24329.

It can be written as a sum of positive squares in 2 ways, for example, as 312481 + 678976 = 559^2 + 824^2 .

It is a cyclic number.

It is not a de Polignac number, because 991457 - 2² = 991453 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991453) 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, 29144 + ... + 29177.

It is an arithmetic number, because the mean of its divisors is an integer number (262449).

2⁹⁹¹⁴⁵⁷ is an apocalyptic number.

It is an amenable number.

991457 is a deficient number, since it is larger than the sum of its proper divisors (58339).

991457 is a wasteful number, since it uses less digits than its factorization.

991457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58338.

The product of its digits is 11340, while the sum is 35.

The square root of 991457 is about 995.7193379663. The cubic root of 991457 is about 99.7144185420.

The spelling of 991457 in words is "nine hundred ninety-one thousand, four hundred fifty-seven".