642684859 has 2 divisors, whose sum is σ = 642684860. Its totient is φ = 642684858.

The previous prime is 642684851. The next prime is 642684869. The reversal of 642684859 is 958486246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642684859 - 2³ = 642684851 is a prime.

It is not a weakly prime, because it can be changed into another prime (642684851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321342429 + 321342430.

It is an arithmetic number, because the mean of its divisors is an integer number (321342430).

Almost surely, 2^642684859 is an apocalyptic number.

642684859 is a deficient number, since it is larger than the sum of its proper divisors (1).

642684859 is an equidigital number, since it uses as much as digits as its factorization.

642684859 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3317760, while the sum is 52.

The square root of 642684859 is about 25351.2299307154. The cubic root of 642684859 is about 862.9772684158.

The spelling of 642684859 in words is "six hundred forty-two million, six hundred eighty-four thousand, eight hundred fifty-nine".