642420859 has 2 divisors, whose sum is σ = 642420860. Its totient is φ = 642420858.

The previous prime is 642420839. The next prime is 642420901. The reversal of 642420859 is 958024246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642420859 - 2⁵ = 642420827 is a prime.

It is not a weakly prime, because it can be changed into another prime (642420839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321210429 + 321210430.

It is an arithmetic number, because the mean of its divisors is an integer number (321210430).

Almost surely, 2^642420859 is an apocalyptic number.

642420859 is a deficient number, since it is larger than the sum of its proper divisors (1).

642420859 is an equidigital number, since it uses as much as digits as its factorization.

642420859 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 138240, while the sum is 40.

The square root of 642420859 is about 25346.0225479265. The cubic root of 642420859 is about 862.8590885655.

The spelling of 642420859 in words is "six hundred forty-two million, four hundred twenty thousand, eight hundred fifty-nine".