991607 has 2 divisors, whose sum is σ = 991608. Its totient is φ = 991606.

The previous prime is 991603. The next prime is 991619. The reversal of 991607 is 706199.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 991607 - 2² = 991603 is a prime.

It is a Chen prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 991607.

It is not a weakly prime, because it can be changed into another prime (991603) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495803 + 495804.

It is an arithmetic number, because the mean of its divisors is an integer number (495804).

2⁹⁹¹⁶⁰⁷ is an apocalyptic number.

991607 is a deficient number, since it is larger than the sum of its proper divisors (1).

991607 is an equidigital number, since it uses as much as digits as its factorization.

991607 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3402, while the sum is 32.

The square root of 991607 is about 995.7946575474. The cubic root of 991607 is about 99.7194469694.

The spelling of 991607 in words is "nine hundred ninety-one thousand, six hundred seven".