20956669 has 2 divisors, whose sum is σ = 20956670. Its totient is φ = 20956668.

The previous prime is 20956643. The next prime is 20956673. The reversal of 20956669 is 96665902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13322500 + 7634169 = 3650^2 + 2763^2 .

It is a cyclic number.

It is not a de Polignac number, because 20956669 - 2¹⁹ = 20432381 is a prime.

It is a super-2 number, since 2×20956669² = 878363951151122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20956679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10478334 + 10478335.

It is an arithmetic number, because the mean of its divisors is an integer number (10478335).

Almost surely, 2^20956669 is an apocalyptic number.

It is an amenable number.

20956669 is a deficient number, since it is larger than the sum of its proper divisors (1).

20956669 is an equidigital number, since it uses as much as digits as its factorization.

20956669 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 174960, while the sum is 43.

The square root of 20956669 is about 4577.8454539226. The cubic root of 20956669 is about 275.7025299214.

The spelling of 20956669 in words is "twenty million, nine hundred fifty-six thousand, six hundred sixty-nine".