1642317920561 has 2 divisors, whose sum is σ = 1642317920562. Its totient is φ = 1642317920560.

The previous prime is 1642317920501. The next prime is 1642317920569. The reversal of 1642317920561 is 1650297132461.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1402187539600 + 240130380961 = 1184140^2 + 490031^2 .

It is a cyclic number.

It is not a de Polignac number, because 1642317920561 - 2²⁶ = 1642250811697 is a prime.

It is not a weakly prime, because it can be changed into another prime (1642317920569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821158960280 + 821158960281.

It is an arithmetic number, because the mean of its divisors is an integer number (821158960281).

Almost surely, 2^{1642317920561} is an apocalyptic number.

It is an amenable number.

1642317920561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1642317920561 is an equidigital number, since it uses as much as digits as its factorization.

1642317920561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 544320, while the sum is 47.

The spelling of 1642317920561 in words is "one trillion, six hundred forty-two billion, three hundred seventeen million, nine hundred twenty thousand, five hundred sixty-one".