20898865 has 16 divisors (see below), whose sum is σ = 28597968. Its totient is φ = 14524416.

The previous prime is 20898863. The next prime is 20898869. The reversal of 20898865 is 56889802.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 720801 + 20178064 = 849^2 + 4492^2 .

It is a cyclic number.

It is not a de Polignac number, because 20898865 - 2¹ = 20898863 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20898863) 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 in 15 ways as a sum of consecutive naturals, for example, 8352 + ... + 10561.

It is an arithmetic number, because the mean of its divisors is an integer number (1787373).

Almost surely, 2^20898865 is an apocalyptic number.

It is an amenable number.

20898865 is a deficient number, since it is larger than the sum of its proper divisors (7699103).

20898865 is a wasteful number, since it uses less digits than its factorization.

20898865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18948.

The product of its (nonzero) digits is 276480, while the sum is 46.

The square root of 20898865 is about 4571.5276440157. The cubic root of 20898865 is about 275.4488098276.

The spelling of 20898865 in words is "twenty million, eight hundred ninety-eight thousand, eight hundred sixty-five".