4251978721 has 2 divisors, whose sum is σ = 4251978722. Its totient is φ = 4251978720.

The previous prime is 4251978713. The next prime is 4251978737. The reversal of 4251978721 is 1278791524.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3923644321 + 328334400 = 62639^2 + 18120^2 .

It is a cyclic number.

It is not a de Polignac number, because 4251978721 - 2³ = 4251978713 is a prime.

It is not a weakly prime, because it can be changed into another prime (4251978701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2125989360 + 2125989361.

It is an arithmetic number, because the mean of its divisors is an integer number (2125989361).

Almost surely, 2^4251978721 is an apocalyptic number.

It is an amenable number.

4251978721 is a deficient number, since it is larger than the sum of its proper divisors (1).

4251978721 is an equidigital number, since it uses as much as digits as its factorization.

4251978721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 282240, while the sum is 46.

The square root of 4251978721 is about 65207.1983833073. The cubic root of 4251978721 is about 1620.0572454750.

The spelling of 4251978721 in words is "four billion, two hundred fifty-one million, nine hundred seventy-eight thousand, seven hundred twenty-one".