20066581 has 2 divisors, whose sum is σ = 20066582. Its totient is φ = 20066580.

The previous prime is 20066569. The next prime is 20066587. The reversal of 20066581 is 18566002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11458225 + 8608356 = 3385^2 + 2934^2 .

It is a cyclic number.

It is not a de Polignac number, because 20066581 - 2¹⁵ = 20033813 is a prime.

It is a super-2 number, since 2×20066581² = 805335346059122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20066587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10033290 + 10033291.

It is an arithmetic number, because the mean of its divisors is an integer number (10033291).

Almost surely, 2^20066581 is an apocalyptic number.

It is an amenable number.

20066581 is a deficient number, since it is larger than the sum of its proper divisors (1).

20066581 is an equidigital number, since it uses as much as digits as its factorization.

20066581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 20066581 is about 4479.5737520438. The cubic root of 20066581 is about 271.7426424226.

The spelling of 20066581 in words is "twenty million, sixty-six thousand, five hundred eighty-one".