621650042161 has 2 divisors, whose sum is σ = 621650042162. Its totient is φ = 621650042160.

The previous prime is 621650042147. The next prime is 621650042171. The reversal of 621650042161 is 161240056126.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 528209168400 + 93440873761 = 726780^2 + 305681^2 .

It is a cyclic number.

It is not a de Polignac number, because 621650042161 - 2²³ = 621641653553 is a prime.

It is not a weakly prime, because it can be changed into another prime (621650042131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310825021080 + 310825021081.

It is an arithmetic number, because the mean of its divisors is an integer number (310825021081).

Almost surely, 2^621650042161 is an apocalyptic number.

It is an amenable number.

621650042161 is a deficient number, since it is larger than the sum of its proper divisors (1).

621650042161 is an equidigital number, since it uses as much as digits as its factorization.

621650042161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 34.

Adding to 621650042161 its reverse (161240056126), we get a palindrome (782890098287).

The spelling of 621650042161 in words is "six hundred twenty-one billion, six hundred fifty million, forty-two thousand, one hundred sixty-one".