616613561021 has 2 divisors, whose sum is σ = 616613561022. Its totient is φ = 616613561020.

The previous prime is 616613560999. The next prime is 616613561041. The reversal of 616613561021 is 120165316616.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 340688179225 + 275925381796 = 583685^2 + 525286^2 .

It is a cyclic number.

It is not a de Polignac number, because 616613561021 - 2²⁶ = 616546452157 is a prime.

It is a super-3 number, since 3×616613561021³ (a number of 36 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (616613561041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 308306780510 + 308306780511.

It is an arithmetic number, because the mean of its divisors is an integer number (308306780511).

Almost surely, 2^616613561021 is an apocalyptic number.

It is an amenable number.

616613561021 is a deficient number, since it is larger than the sum of its proper divisors (1).

616613561021 is an equidigital number, since it uses as much as digits as its factorization.

616613561021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 38880, while the sum is 38.

Adding to 616613561021 its reverse (120165316616), we get a palindrome (736778877637).

The spelling of 616613561021 in words is "six hundred sixteen billion, six hundred thirteen million, five hundred sixty-one thousand, twenty-one".