206643949979 has 2 divisors, whose sum is σ = 206643949980. Its totient is φ = 206643949978.

The previous prime is 206643949909. The next prime is 206643950027. The reversal of 206643949979 is 979949346602.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 206643949979 - 2⁸ = 206643949723 is a prime.

It is not a weakly prime, because it can be changed into another prime (206643949909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103321974989 + 103321974990.

It is an arithmetic number, because the mean of its divisors is an integer number (103321974990).

Almost surely, 2^206643949979 is an apocalyptic number.

206643949979 is a deficient number, since it is larger than the sum of its proper divisors (1).

206643949979 is an equidigital number, since it uses as much as digits as its factorization.

206643949979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 158723712, while the sum is 68.

The spelling of 206643949979 in words is "two hundred six billion, six hundred forty-three million, nine hundred forty-nine thousand, nine hundred seventy-nine".