20956897 has 4 divisors (see below), whose sum is σ = 22568980. Its totient is φ = 19344816.

The previous prime is 20956861. The next prime is 20956907. The reversal of 20956897 is 79865902.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12453841 + 8503056 = 3529^2 + 2916^2 .

It is a cyclic number.

It is not a de Polignac number, because 20956897 - 2¹⁹ = 20432609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20956807) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 806022 + ... + 806047.

It is an arithmetic number, because the mean of its divisors is an integer number (5642245).

Almost surely, 2^20956897 is an apocalyptic number.

It is an amenable number.

20956897 is a deficient number, since it is larger than the sum of its proper divisors (1612083).

20956897 is a wasteful number, since it uses less digits than its factorization.

20956897 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1612082.

The product of its (nonzero) digits is 272160, while the sum is 46.

The square root of 20956897 is about 4577.8703563994. The cubic root of 20956897 is about 275.7035297615.

The spelling of 20956897 in words is "twenty million, nine hundred fifty-six thousand, eight hundred ninety-seven".