20817061 has 4 divisors (see below), whose sum is σ = 22041612. Its totient is φ = 19592512.

The previous prime is 20817059. The next prime is 20817077. The reversal of 20817061 is 16071802.

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 11088900 + 9728161 = 3330^2 + 3119^2 .

It is a cyclic number.

It is not a de Polignac number, because 20817061 - 2¹ = 20817059 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20817091) 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 3 ways as a sum of consecutive naturals, for example, 612250 + ... + 612283.

It is an arithmetic number, because the mean of its divisors is an integer number (5510403).

Almost surely, 2^20817061 is an apocalyptic number.

It is an amenable number.

20817061 is a deficient number, since it is larger than the sum of its proper divisors (1224551).

20817061 is a wasteful number, since it uses less digits than its factorization.

20817061 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1224550.

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 20817061 is about 4562.5717528604. The cubic root of 20817061 is about 275.0889453333.

Adding to 20817061 its reverse (16071802), we get a palindrome (36888863).

The spelling of 20817061 in words is "twenty million, eight hundred seventeen thousand, sixty-one".