247143991 has 2 divisors, whose sum is σ = 247143992. Its totient is φ = 247143990.

The previous prime is 247143989. The next prime is 247144021. The reversal of 247143991 is 199341742.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 247143991 - 2¹ = 247143989 is a prime.

It is a super-2 number, since 2×247143991² = 122160304574816162, which contains 22 as substring.

Together with 247143989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (247143931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 123571995 + 123571996.

It is an arithmetic number, because the mean of its divisors is an integer number (123571996).

Almost surely, 2^247143991 is an apocalyptic number.

247143991 is a deficient number, since it is larger than the sum of its proper divisors (1).

247143991 is an equidigital number, since it uses as much as digits as its factorization.

247143991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 54432, while the sum is 40.

The square root of 247143991 is about 15720.8139420324. The cubic root of 247143991 is about 627.5524342570.

The spelling of 247143991 in words is "two hundred forty-seven million, one hundred forty-three thousand, nine hundred ninety-one".