9555991 has 2 divisors, whose sum is σ = 9555992. Its totient is φ = 9555990.

The previous prime is 9555983. The next prime is 9556003. The reversal of 9555991 is 1995559.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9555991 - 2³ = 9555983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9555901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4777995 + 4777996.

It is an arithmetic number, because the mean of its divisors is an integer number (4777996).

Almost surely, 2^9555991 is an apocalyptic number.

9555991 is a deficient number, since it is larger than the sum of its proper divisors (1).

9555991 is an equidigital number, since it uses as much as digits as its factorization.

9555991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 91125, while the sum is 43.

The square root of 9555991 is about 3091.2765971359. The cubic root of 9555991 is about 212.2064486488.

The spelling of 9555991 in words is "nine million, five hundred fifty-five thousand, nine hundred ninety-one".