7643784121 has 2 divisors, whose sum is σ = 7643784122. Its totient is φ = 7643784120.

The previous prime is 7643784061. The next prime is 7643784149. The reversal of 7643784121 is 1214873467.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 6783828496 + 859955625 = 82364^2 + 29325^2 .

It is a cyclic number.

It is not a de Polignac number, because 7643784121 - 2¹³ = 7643775929 is a prime.

It is not a weakly prime, because it can be changed into another prime (7643788121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3821892060 + 3821892061.

It is an arithmetic number, because the mean of its divisors is an integer number (3821892061).

Almost surely, 2^7643784121 is an apocalyptic number.

It is an amenable number.

7643784121 is a deficient number, since it is larger than the sum of its proper divisors (1).

7643784121 is an equidigital number, since it uses as much as digits as its factorization.

7643784121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 225792, while the sum is 43.

The square root of 7643784121 is about 87428.7373865138. The cubic root of 7643784121 is about 1969.8635205682.

The spelling of 7643784121 in words is "seven billion, six hundred forty-three million, seven hundred eighty-four thousand, one hundred twenty-one".