642260389 has 2 divisors, whose sum is σ = 642260390. Its totient is φ = 642260388.

The previous prime is 642260383. The next prime is 642260429. The reversal of 642260389 is 983062246.

It is an a-pointer prime, because the next prime (642260429) can be obtained adding 642260389 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 575184289 + 67076100 = 23983^2 + 8190^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642260389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642260383) 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, 321130194 + 321130195.

It is an arithmetic number, because the mean of its divisors is an integer number (321130195).

Almost surely, 2^642260389 is an apocalyptic number.

It is an amenable number.

642260389 is a deficient number, since it is larger than the sum of its proper divisors (1).

642260389 is an equidigital number, since it uses as much as digits as its factorization.

642260389 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 124416, while the sum is 40.

The square root of 642260389 is about 25342.8567647769. The cubic root of 642260389 is about 862.7872381959.

The spelling of 642260389 in words is "six hundred forty-two million, two hundred sixty thousand, three hundred eighty-nine".