8219542421 has 2 divisors, whose sum is σ = 8219542422. Its totient is φ = 8219542420.

The previous prime is 8219542403. The next prime is 8219542543. The reversal of 8219542421 is 1242459128.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7597039921 + 622502500 = 87161^2 + 24950^2 .

It is a cyclic number.

It is not a de Polignac number, because 8219542421 - 2¹⁴ = 8219526037 is a prime.

It is a super-2 number, since 2×8219542421² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8219542021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4109771210 + 4109771211.

It is an arithmetic number, because the mean of its divisors is an integer number (4109771211).

Almost surely, 2^8219542421 is an apocalyptic number.

It is an amenable number.

8219542421 is a deficient number, since it is larger than the sum of its proper divisors (1).

8219542421 is an equidigital number, since it uses as much as digits as its factorization.

8219542421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46080, while the sum is 38.

The square root of 8219542421 is about 90661.6921362049. The cubic root of 8219542421 is about 2018.1303503137.

The spelling of 8219542421 in words is "eight billion, two hundred nineteen million, five hundred forty-two thousand, four hundred twenty-one".