20965649 has 2 divisors, whose sum is σ = 20965650. Its totient is φ = 20965648.

The previous prime is 20965621. The next prime is 20965663. The reversal of 20965649 is 94656902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20566225 + 399424 = 4535^2 + 632^2 .

It is a cyclic number.

It is not a de Polignac number, because 20965649 - 2²⁴ = 4188433 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20965669) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10482824 + 10482825.

It is an arithmetic number, because the mean of its divisors is an integer number (10482825).

Almost surely, 2^20965649 is an apocalyptic number.

It is an amenable number.

20965649 is a deficient number, since it is larger than the sum of its proper divisors (1).

20965649 is an equidigital number, since it uses as much as digits as its factorization.

20965649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 116640, while the sum is 41.

The square root of 20965649 is about 4578.8261596178. The cubic root of 20965649 is about 275.7419041046.

The spelling of 20965649 in words is "twenty million, nine hundred sixty-five thousand, six hundred forty-nine".