247319921 has 2 divisors, whose sum is σ = 247319922. Its totient is φ = 247319920.

The previous prime is 247319911. The next prime is 247319923. The reversal of 247319921 is 129913742.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 246490000 + 829921 = 15700^2 + 911^2 .

It is a cyclic number.

It is not a de Polignac number, because 247319921 - 2⁶ = 247319857 is a prime.

It is a super-2 number, since 2×247319921² = 122334286646892482, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 247319923, it forms a pair of twin primes.

It is a Chen prime.

It is a pancake number, because a pancake can be divided into 247319921 parts by 22240 straight cuts.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (247319923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 123659960 + 123659961.

It is an arithmetic number, because the mean of its divisors is an integer number (123659961).

Almost surely, 2^247319921 is an apocalyptic number.

It is an amenable number.

247319921 is a deficient number, since it is larger than the sum of its proper divisors (1).

247319921 is an equidigital number, since it uses as much as digits as its factorization.

247319921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27216, while the sum is 38.

The square root of 247319921 is about 15726.4083947989. The cubic root of 247319921 is about 627.7013071364.

The spelling of 247319921 in words is "two hundred forty-seven million, three hundred nineteen thousand, nine hundred twenty-one".