20019281 has 2 divisors, whose sum is σ = 20019282. Its totient is φ = 20019280.

The previous prime is 20019277. The next prime is 20019299. The reversal of 20019281 is 18291002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10923025 + 9096256 = 3305^2 + 3016^2 .

It is a cyclic number.

It is not a de Polignac number, because 20019281 - 2² = 20019277 is a prime.

It is a super-2 number, since 2×20019281² = 801543223513922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (20019221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10009640 + 10009641.

It is an arithmetic number, because the mean of its divisors is an integer number (10009641).

Almost surely, 2^20019281 is an apocalyptic number.

It is an amenable number.

20019281 is a deficient number, since it is larger than the sum of its proper divisors (1).

20019281 is an equidigital number, since it uses as much as digits as its factorization.

20019281 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 20019281 is about 4474.2911170374. The cubic root of 20019281 is about 271.5289614539.

The spelling of 20019281 in words is "twenty million, nineteen thousand, two hundred eighty-one".