20208861 has 6 divisors (see below), whose sum is σ = 29190590. Its totient is φ = 13472568.

The previous prime is 20208833. The next prime is 20208863. The reversal of 20208861 is 16880202.

It can be written as a sum of positive squares in only one way, i.e., 20115225 + 93636 = 4485^2 + 306^2 .

It is not a de Polignac number, because 20208861 - 2⁵ = 20208829 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20208863) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1122706 + ... + 1122723.

Almost surely, 2^20208861 is an apocalyptic number.

It is an amenable number.

20208861 is a deficient number, since it is larger than the sum of its proper divisors (8981729).

20208861 is a wasteful number, since it uses less digits than its factorization.

20208861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2245435 (or 2245432 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 20208861 is about 4495.4266760787. The cubic root of 20208861 is about 272.3833847176.

The spelling of 20208861 in words is "twenty million, two hundred eight thousand, eight hundred sixty-one".