991686203 has 2 divisors, whose sum is σ = 991686204. Its totient is φ = 991686202.

The previous prime is 991686169. The next prime is 991686221. The reversal of 991686203 is 302686199.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 991686203 - 2¹⁶ = 991620667 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (991686263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495843101 + 495843102.

It is an arithmetic number, because the mean of its divisors is an integer number (495843102).

Almost surely, 2^991686203 is an apocalyptic number.

991686203 is a deficient number, since it is larger than the sum of its proper divisors (1).

991686203 is an equidigital number, since it uses as much as digits as its factorization.

991686203 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 139968, while the sum is 44.

The square root of 991686203 is about 31491.0495696793. The cubic root of 991686203 is about 997.2210187503.

The spelling of 991686203 in words is "nine hundred ninety-one million, six hundred eighty-six thousand, two hundred three".