642019717 has 2 divisors, whose sum is σ = 642019718. Its totient is φ = 642019716.

The previous prime is 642019699. The next prime is 642019727. The reversal of 642019717 is 717910246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 517608001 + 124411716 = 22751^2 + 11154^2 .

It is a cyclic number.

It is not a de Polignac number, because 642019717 - 2⁷ = 642019589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642019727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321009858 + 321009859.

It is an arithmetic number, because the mean of its divisors is an integer number (321009859).

Almost surely, 2^642019717 is an apocalyptic number.

It is an amenable number.

642019717 is a deficient number, since it is larger than the sum of its proper divisors (1).

642019717 is an equidigital number, since it uses as much as digits as its factorization.

642019717 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 642019717 is about 25338.1079996120. The cubic root of 642019717 is about 862.6794549789.

The spelling of 642019717 in words is "six hundred forty-two million, nineteen thousand, seven hundred seventeen".