209800979 has 2 divisors, whose sum is σ = 209800980. Its totient is φ = 209800978.

The previous prime is 209800973. The next prime is 209801003. The reversal of 209800979 is 979008902.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-209800979 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (209800973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104900489 + 104900490.

It is an arithmetic number, because the mean of its divisors is an integer number (104900490).

Almost surely, 2^209800979 is an apocalyptic number.

209800979 is a deficient number, since it is larger than the sum of its proper divisors (1).

209800979 is an equidigital number, since it uses as much as digits as its factorization.

209800979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 81648, while the sum is 44.

The square root of 209800979 is about 14484.5082415662. The cubic root of 209800979 is about 594.2043636582.

The spelling of 209800979 in words is "two hundred nine million, eight hundred thousand, nine hundred seventy-nine".