42718215821 has 2 divisors, whose sum is σ = 42718215822. Its totient is φ = 42718215820.

The previous prime is 42718215809. The next prime is 42718215829. The reversal of 42718215821 is 12851281724.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 32560398025 + 10157817796 = 180445^2 + 100786^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42718215821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42718215829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21359107910 + 21359107911.

It is an arithmetic number, because the mean of its divisors is an integer number (21359107911).

Almost surely, 2^42718215821 is an apocalyptic number.

It is an amenable number.

42718215821 is a deficient number, since it is larger than the sum of its proper divisors (1).

42718215821 is an equidigital number, since it uses as much as digits as its factorization.

42718215821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 71680, while the sum is 41.

The spelling of 42718215821 in words is "forty-two billion, seven hundred eighteen million, two hundred fifteen thousand, eight hundred twenty-one".