247421 has 2 divisors, whose sum is σ = 247422.
Its totient is φ = 247420.
The previous prime is 247409. The next prime is 247433. The reversal of 247421 is 124742.
It is a balanced prime because it is at equal distance from previous prime (247409) and next prime (247433).
It can be written as a sum of positive squares in only one way, i.e., 151321 + 96100 = 389^2 + 310^2
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-247421 is a prime.
It is a super-2 number, since 2×2474212 = 122434302482, which contains 22 as substring.
It is a Sophie Germain prime.
It is a Curzon number.
It is equal to p21827 and since 247421 and 21827 have the same sum of digits, it is a Honaker prime.
It is a junction number, because it is equal to n+sod(n) for n = 247393 and 247402.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (247451) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 123710 + 123711.
It is an arithmetic number, because the mean of its divisors is an integer number (123711).
2247421 is an apocalyptic number.
It is an amenable number.
247421 is a deficient number, since it is larger than the sum of its proper divisors (1).
247421 is an equidigital number, since it uses as much as digits as its factorization.
247421 is an evil number, because the sum of its binary digits is even.
The product of its digits is 448, while the sum is 20.
The square root of 247421 is about 497.4143142291.
The cubic root of 247421 is about 62.7786808779.
The spelling of 247421 in words is "two hundred forty-seven thousand, four hundred twenty-one", and thus it is an iban number.