642091169 has 2 divisors, whose sum is σ = 642091170. Its totient is φ = 642091168.

The previous prime is 642091133. The next prime is 642091231. The reversal of 642091169 is 961190246.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 639482944 + 2608225 = 25288^2 + 1615^2 .

It is a cyclic number.

It is not a de Polignac number, because 642091169 - 2⁸ = 642090913 is a prime.

It is a super-2 number, since 2×642091169² = 824562138615573122, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (642091469) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321045584 + 321045585.

It is an arithmetic number, because the mean of its divisors is an integer number (321045585).

Almost surely, 2^642091169 is an apocalyptic number.

It is an amenable number.

642091169 is a deficient number, since it is larger than the sum of its proper divisors (1).

642091169 is an equidigital number, since it uses as much as digits as its factorization.

642091169 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 642091169 is about 25339.5179314840. The cubic root of 642091169 is about 862.7114570520.

The spelling of 642091169 in words is "six hundred forty-two million, ninety-one thousand, one hundred sixty-nine".