20280681 has 6 divisors (see below), whose sum is σ = 29294330. Its totient is φ = 13520448.

The previous prime is 20280679. The next prime is 20280683. The reversal of 20280681 is 18608202.

It is an interprime number because it is at equal distance from previous prime (20280679) and next prime (20280683).

It can be written as a sum of positive squares in only one way, i.e., 18275625 + 2005056 = 4275^2 + 1416^2 .

It is not a de Polignac number, because 20280681 - 2¹ = 20280679 is a prime.

It is a super-2 number, since 2×20280681² = 822612043647522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20280683) 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, 1126696 + ... + 1126713.

Almost surely, 2^20280681 is an apocalyptic number.

It is an amenable number.

20280681 is a deficient number, since it is larger than the sum of its proper divisors (9013649).

20280681 is a wasteful number, since it uses less digits than its factorization.

20280681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2253415 (or 2253412 counting only the distinct ones).

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

The square root of 20280681 is about 4503.4077097238. The cubic root of 20280681 is about 272.7056764414.

Adding to 20280681 its reverse (18608202), we get a palindrome (38888883).

The spelling of 20280681 in words is "twenty million, two hundred eighty thousand, six hundred eighty-one".