621206180081 has 2 divisors, whose sum is σ = 621206180082. Its totient is φ = 621206180080.

The previous prime is 621206180059. The next prime is 621206180087. The reversal of 621206180081 is 180081602126.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 618085281856 + 3120898225 = 786184^2 + 55865^2 .

It is a cyclic number.

It is not a de Polignac number, because 621206180081 - 2¹⁰ = 621206179057 is a prime.

It is a super-2 number, since 2×621206180081² (a number of 24 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (621206180087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 310603090040 + 310603090041.

It is an arithmetic number, because the mean of its divisors is an integer number (310603090041).

Almost surely, 2^621206180081 is an apocalyptic number.

It is an amenable number.

621206180081 is a deficient number, since it is larger than the sum of its proper divisors (1).

621206180081 is an equidigital number, since it uses as much as digits as its factorization.

621206180081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9216, while the sum is 35.

The spelling of 621206180081 in words is "six hundred twenty-one billion, two hundred six million, one hundred eighty thousand, eighty-one".