641616121 has 2 divisors, whose sum is σ = 641616122. Its totient is φ = 641616120.

The previous prime is 641616113. The next prime is 641616127. The reversal of 641616121 is 121616146.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 559984896 + 81631225 = 23664^2 + 9035^2 .

It is a cyclic number.

It is not a de Polignac number, because 641616121 - 2³ = 641616113 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 641616121.

It is not a weakly prime, because it can be changed into another prime (641616127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320808060 + 320808061.

It is an arithmetic number, because the mean of its divisors is an integer number (320808061).

Almost surely, 2^641616121 is an apocalyptic number.

It is an amenable number.

641616121 is a deficient number, since it is larger than the sum of its proper divisors (1).

641616121 is an equidigital number, since it uses as much as digits as its factorization.

641616121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 28.

The square root of 641616121 is about 25330.1425380909. The cubic root of 641616121 is about 862.4986469488.

The spelling of 641616121 in words is "six hundred forty-one million, six hundred sixteen thousand, one hundred twenty-one".