247428781 has 2 divisors, whose sum is σ = 247428782. Its totient is φ = 247428780.

The previous prime is 247428737. The next prime is 247428791. The reversal of 247428781 is 187824742.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 246772681 + 656100 = 15709^2 + 810^2 .

It is a cyclic number.

It is not a de Polignac number, because 247428781 - 2¹⁷ = 247297709 is a prime.

It is a super-2 number, since 2×247428781² = 122442003334291922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (247428721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 123714390 + 123714391.

It is an arithmetic number, because the mean of its divisors is an integer number (123714391).

Almost surely, 2^247428781 is an apocalyptic number.

It is an amenable number.

247428781 is a deficient number, since it is larger than the sum of its proper divisors (1).

247428781 is an equidigital number, since it uses as much as digits as its factorization.

247428781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 200704, while the sum is 43.

The square root of 247428781 is about 15729.8690712924. The cubic root of 247428781 is about 627.7933896786.

The spelling of 247428781 in words is "two hundred forty-seven million, four hundred twenty-eight thousand, seven hundred eighty-one".