642052591 has 2 divisors, whose sum is σ = 642052592. Its totient is φ = 642052590.

The previous prime is 642052517. The next prime is 642052597. The reversal of 642052591 is 195250246.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642052591 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642052597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321026295 + 321026296.

It is an arithmetic number, because the mean of its divisors is an integer number (321026296).

Almost surely, 2^642052591 is an apocalyptic number.

642052591 is a deficient number, since it is larger than the sum of its proper divisors (1).

642052591 is an equidigital number, since it uses as much as digits as its factorization.

642052591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21600, while the sum is 34.

The square root of 642052591 is about 25338.7566979913. The cubic root of 642052591 is about 862.6941789505.

The spelling of 642052591 in words is "six hundred forty-two million, fifty-two thousand, five hundred ninety-one".