642066201991 has 2 divisors, whose sum is σ = 642066201992. Its totient is φ = 642066201990.

The previous prime is 642066201983. The next prime is 642066202031. The reversal of 642066201991 is 199102660246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642066201991 - 2³ = 642066201983 is a prime.

It is a super-2 number, since 2×642066201991² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642066201691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321033100995 + 321033100996.

It is an arithmetic number, because the mean of its divisors is an integer number (321033100996).

Almost surely, 2^642066201991 is an apocalyptic number.

642066201991 is a deficient number, since it is larger than the sum of its proper divisors (1).

642066201991 is an equidigital number, since it uses as much as digits as its factorization.

642066201991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 279936, while the sum is 46.

The spelling of 642066201991 in words is "six hundred forty-two billion, sixty-six million, two hundred one thousand, nine hundred ninety-one".