20980987 has 2 divisors, whose sum is σ = 20980988. Its totient is φ = 20980986.

The previous prime is 20980957. The next prime is 20981027. The reversal of 20980987 is 78908902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20980987 - 2⁷ = 20980859 is a prime.

It is not a weakly prime, because it can be changed into another prime (20980957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10490493 + 10490494.

It is an arithmetic number, because the mean of its divisors is an integer number (10490494).

Almost surely, 2^20980987 is an apocalyptic number.

20980987 is a deficient number, since it is larger than the sum of its proper divisors (1).

20980987 is an equidigital number, since it uses as much as digits as its factorization.

20980987 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72576, while the sum is 43.

The square root of 20980987 is about 4580.5007368191. The cubic root of 20980987 is about 275.8091299174.

The spelling of 20980987 in words is "twenty million, nine hundred eighty thousand, nine hundred eighty-seven".