658991 has 2 divisors, whose sum is σ = 658992. Its totient is φ = 658990.

The previous prime is 658979. The next prime is 658997. The reversal of 658991 is 199856.

658991 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-658991 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (658997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 329495 + 329496.

It is an arithmetic number, because the mean of its divisors is an integer number (329496).

2⁶⁵⁸⁹⁹¹ is an apocalyptic number.

658991 is a deficient number, since it is larger than the sum of its proper divisors (1).

658991 is an equidigital number, since it uses as much as digits as its factorization.

658991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19440, while the sum is 38.

The square root of 658991 is about 811.7826063670. The cubic root of 658991 is about 87.0214858635.

The spelling of 658991 in words is "six hundred fifty-eight thousand, nine hundred ninety-one".