20866061 has 4 divisors (see below), whose sum is σ = 20943900. Its totient is φ = 20788224.

The previous prime is 20866057. The next prime is 20866081. The reversal of 20866061 is 16066802.

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 4818025 + 16048036 = 2195^2 + 4006^2 .

It is a cyclic number.

It is not a de Polignac number, because 20866061 - 2² = 20866057 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 (20866031) 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, 38516 + ... + 39053.

It is an arithmetic number, because the mean of its divisors is an integer number (5235975).

Almost surely, 2^20866061 is an apocalyptic number.

It is an amenable number.

20866061 is a deficient number, since it is larger than the sum of its proper divisors (77839).

20866061 is an equidigital number, since it uses as much as digits as its factorization.

20866061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77838.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 20866061 is about 4567.9383752411. The cubic root of 20866061 is about 275.3046145233.

The spelling of 20866061 in words is "twenty million, eight hundred sixty-six thousand, sixty-one".