642220817807 has 2 divisors, whose sum is σ = 642220817808. Its totient is φ = 642220817806.

The previous prime is 642220817803. The next prime is 642220817857. The reversal of 642220817807 is 708718022246.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642220817807 - 2² = 642220817803 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642220817803) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321110408903 + 321110408904.

It is an arithmetic number, because the mean of its divisors is an integer number (321110408904).

Almost surely, 2^642220817807 is an apocalyptic number.

642220817807 is a deficient number, since it is larger than the sum of its proper divisors (1).

642220817807 is an equidigital number, since it uses as much as digits as its factorization.

642220817807 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 602112, while the sum is 47.

The spelling of 642220817807 in words is "six hundred forty-two billion, two hundred twenty million, eight hundred seventeen thousand, eight hundred seven".