626601556561 has 2 divisors, whose sum is σ = 626601556562. Its totient is φ = 626601556560.

The previous prime is 626601556541. The next prime is 626601556661. The reversal of 626601556561 is 165655106626.

626601556561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 626598896400 + 2660161 = 791580^2 + 1631^2 .

It is a cyclic number.

It is not a de Polignac number, because 626601556561 - 2¹⁹ = 626601032273 is a prime.

It is a super-3 number, since 3×626601556561³ (a number of 36 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (626601556501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 313300778280 + 313300778281.

It is an arithmetic number, because the mean of its divisors is an integer number (313300778281).

Almost surely, 2^626601556561 is an apocalyptic number.

It is an amenable number.

626601556561 is a deficient number, since it is larger than the sum of its proper divisors (1).

626601556561 is an equidigital number, since it uses as much as digits as its factorization.

626601556561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944000, while the sum is 49.

The spelling of 626601556561 in words is "six hundred twenty-six billion, six hundred one million, five hundred fifty-six thousand, five hundred sixty-one".