642734112661 has 2 divisors, whose sum is σ = 642734112662. Its totient is φ = 642734112660.

The previous prime is 642734112641. The next prime is 642734112697. The reversal of 642734112661 is 166211437246.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 628999679025 + 13734433636 = 793095^2 + 117194^2 .

It is a cyclic number.

It is not a de Polignac number, because 642734112661 - 2⁷ = 642734112533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642734112641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321367056330 + 321367056331.

It is an arithmetic number, because the mean of its divisors is an integer number (321367056331).

Almost surely, 2^642734112661 is an apocalyptic number.

It is an amenable number.

642734112661 is a deficient number, since it is larger than the sum of its proper divisors (1).

642734112661 is an equidigital number, since it uses as much as digits as its factorization.

642734112661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 290304, while the sum is 43.

The spelling of 642734112661 in words is "six hundred forty-two billion, seven hundred thirty-four million, one hundred twelve thousand, six hundred sixty-one".