991357 has 2 divisors, whose sum is σ = 991358. Its totient is φ = 991356.

The previous prime is 991343. The next prime is 991381. The reversal of 991357 is 753199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 755161 + 236196 = 869^2 + 486^2 .

It is a cyclic number.

It is not a de Polignac number, because 991357 - 2⁷ = 991229 is a prime.

It is equal to p₇₇₈₇₅ and since 991357 and 77875 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991327) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495678 + 495679.

It is an arithmetic number, because the mean of its divisors is an integer number (495679).

2⁹⁹¹³⁵⁷ is an apocalyptic number.

It is an amenable number.

991357 is a deficient number, since it is larger than the sum of its proper divisors (1).

991357 is an equidigital number, since it uses as much as digits as its factorization.

991357 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8505, while the sum is 34.

The square root of 991357 is about 995.6691217468. The cubic root of 991357 is about 99.7110659753.

The spelling of 991357 in words is "nine hundred ninety-one thousand, three hundred fifty-seven".