642581287 has 2 divisors, whose sum is σ = 642581288. Its totient is φ = 642581286.

The previous prime is 642581281. The next prime is 642581353. The reversal of 642581287 is 782185246.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642581287 - 2¹¹ = 642579239 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642581281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321290643 + 321290644.

It is an arithmetic number, because the mean of its divisors is an integer number (321290644).

Almost surely, 2^642581287 is an apocalyptic number.

642581287 is a deficient number, since it is larger than the sum of its proper divisors (1).

642581287 is an equidigital number, since it uses as much as digits as its factorization.

642581287 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 215040, while the sum is 43.

The square root of 642581287 is about 25349.1871072822. The cubic root of 642581287 is about 862.9309081703.

The spelling of 642581287 in words is "six hundred forty-two million, five hundred eighty-one thousand, two hundred eighty-seven".