20284681 has 4 divisors (see below), whose sum is σ = 20295172. Its totient is φ = 20274192.

The previous prime is 20284669. The next prime is 20284697. The reversal of 20284681 is 18648202.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 18648202 = 2 ⋅9324101.

It can be written as a sum of positive squares in 2 ways, for example, as 7209225 + 13075456 = 2685^2 + 3616^2 .

It is a cyclic number.

It is not a de Polignac number, because 20284681 - 2¹³ = 20276489 is a prime.

It is a super-2 number, since 2×20284681² = 822936566543522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20284651) 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, 1410 + ... + 6523.

It is an arithmetic number, because the mean of its divisors is an integer number (5073793).

Almost surely, 2^20284681 is an apocalyptic number.

It is an amenable number.

20284681 is a deficient number, since it is larger than the sum of its proper divisors (10491).

20284681 is an equidigital number, since it uses as much as digits as its factorization.

20284681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10490.

The product of its (nonzero) digits is 6144, while the sum is 31.

The square root of 20284681 is about 4503.8517959631. The cubic root of 20284681 is about 272.7236040281.

The spelling of 20284681 in words is "twenty million, two hundred eighty-four thousand, six hundred eighty-one".