8643142421 has 2 divisors, whose sum is σ = 8643142422. Its totient is φ = 8643142420.

The previous prime is 8643142393. The next prime is 8643142477. The reversal of 8643142421 is 1242413468.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5581733521 + 3061408900 = 74711^2 + 55330^2 .

It is a cyclic number.

It is not a de Polignac number, because 8643142421 - 2⁶ = 8643142357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8643142481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4321571210 + 4321571211.

It is an arithmetic number, because the mean of its divisors is an integer number (4321571211).

Almost surely, 2^8643142421 is an apocalyptic number.

It is an amenable number.

8643142421 is a deficient number, since it is larger than the sum of its proper divisors (1).

8643142421 is an equidigital number, since it uses as much as digits as its factorization.

8643142421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36864, while the sum is 35.

The square root of 8643142421 is about 92968.5023058885. The cubic root of 8643142421 is about 2052.2198773547.

Adding to 8643142421 its reverse (1242413468), we get a palindrome (9885555889).

The spelling of 8643142421 in words is "eight billion, six hundred forty-three million, one hundred forty-two thousand, four hundred twenty-one".