642466325561 has 2 divisors, whose sum is σ = 642466325562. Its totient is φ = 642466325560.

The previous prime is 642466325533. The next prime is 642466325573. The reversal of 642466325561 is 165523664246.

642466325561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 642233946025 + 232379536 = 801395^2 + 15244^2 .

It is a cyclic number.

It is not a de Polignac number, because 642466325561 - 2¹⁰ = 642466324537 is a prime.

It is not a weakly prime, because it can be changed into another prime (642466321561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321233162780 + 321233162781.

It is an arithmetic number, because the mean of its divisors is an integer number (321233162781).

Almost surely, 2^642466325561 is an apocalyptic number.

It is an amenable number.

642466325561 is a deficient number, since it is larger than the sum of its proper divisors (1).

642466325561 is an equidigital number, since it uses as much as digits as its factorization.

642466325561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6220800, while the sum is 50.

The spelling of 642466325561 in words is "six hundred forty-two billion, four hundred sixty-six million, three hundred twenty-five thousand, five hundred sixty-one".