549667991 has 2 divisors, whose sum is σ = 549667992. Its totient is φ = 549667990.

The previous prime is 549667981. The next prime is 549668051. The reversal of 549667991 is 199766945.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 549667991 - 2⁶ = 549667927 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (549667901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 274833995 + 274833996.

It is an arithmetic number, because the mean of its divisors is an integer number (274833996).

Almost surely, 2^549667991 is an apocalyptic number.

549667991 is a deficient number, since it is larger than the sum of its proper divisors (1).

549667991 is an equidigital number, since it uses as much as digits as its factorization.

549667991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3674160, while the sum is 56.

The square root of 549667991 is about 23444.9992748987. Note that the first 3 decimals coincide. The cubic root of 549667991 is about 819.1563755766.

The spelling of 549667991 in words is "five hundred forty-nine million, six hundred sixty-seven thousand, nine hundred ninety-one".