216741539821 has 2 divisors, whose sum is σ = 216741539822. Its totient is φ = 216741539820.

The previous prime is 216741539809. The next prime is 216741539867. The reversal of 216741539821 is 128935147612.

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., 216741458025 + 81796 = 465555^2 + 286^2 .

It is a cyclic number.

It is not a de Polignac number, because 216741539821 - 2⁹ = 216741539309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216741539891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108370769910 + 108370769911.

It is an arithmetic number, because the mean of its divisors is an integer number (108370769911).

Almost surely, 2^216741539821 is an apocalyptic number.

It is an amenable number.

216741539821 is a deficient number, since it is larger than the sum of its proper divisors (1).

216741539821 is an equidigital number, since it uses as much as digits as its factorization.

216741539821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 725760, while the sum is 49.

The spelling of 216741539821 in words is "two hundred sixteen billion, seven hundred forty-one million, five hundred thirty-nine thousand, eight hundred twenty-one".