20916949 has 2 divisors, whose sum is σ = 20916950. Its totient is φ = 20916948.

The previous prime is 20916947. The next prime is 20916979. The reversal of 20916949 is 94961902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15944049 + 4972900 = 3993^2 + 2230^2 .

It is a cyclic number.

It is not a de Polignac number, because 20916949 - 2¹ = 20916947 is a prime.

Together with 20916947, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20916941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10458474 + 10458475.

It is an arithmetic number, because the mean of its divisors is an integer number (10458475).

Almost surely, 2^20916949 is an apocalyptic number.

It is an amenable number.

20916949 is a deficient number, since it is larger than the sum of its proper divisors (1).

20916949 is an equidigital number, since it uses as much as digits as its factorization.

20916949 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 34992, while the sum is 40.

The square root of 20916949 is about 4573.5051109625. The cubic root of 20916949 is about 275.5282364727.

The spelling of 20916949 in words is "twenty million, nine hundred sixteen thousand, nine hundred forty-nine".