20951617 has 2 divisors, whose sum is σ = 20951618. Its totient is φ = 20951616.

The previous prime is 20951611. The next prime is 20951647. The reversal of 20951617 is 71615902.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20757136 + 194481 = 4556^2 + 441^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20951617 is a prime.

It is not a weakly prime, because it can be changed into another prime (20951611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10475808 + 10475809.

It is an arithmetic number, because the mean of its divisors is an integer number (10475809).

Almost surely, 2^20951617 is an apocalyptic number.

It is an amenable number.

20951617 is a deficient number, since it is larger than the sum of its proper divisors (1).

20951617 is an equidigital number, since it uses as much as digits as its factorization.

20951617 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3780, while the sum is 31.

The square root of 20951617 is about 4577.2936327048. The cubic root of 20951617 is about 275.6803737108.

The spelling of 20951617 in words is "twenty million, nine hundred fifty-one thousand, six hundred seventeen".