20252681 has 4 divisors (see below), whose sum is σ = 20261700. Its totient is φ = 20243664.

The previous prime is 20252663. The next prime is 20252707. The reversal of 20252681 is 18625202.

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: 18625202 = 2 ⋅9312601.

It can be written as a sum of positive squares in 2 ways, for example, as 12187081 + 8065600 = 3491^2 + 2840^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20252681 is a prime.

It is a super-2 number, since 2×20252681² = 820342175375522, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20252681.

It is not an unprimeable number, because it can be changed into a prime (20252611) 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, 1835 + ... + 6623.

It is an arithmetic number, because the mean of its divisors is an integer number (5065425).

Almost surely, 2^20252681 is an apocalyptic number.

It is an amenable number.

20252681 is a deficient number, since it is larger than the sum of its proper divisors (9019).

20252681 is an equidigital number, since it uses as much as digits as its factorization.

20252681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9018.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 20252681 is about 4500.2978790298. The cubic root of 20252681 is about 272.5801172837.

Adding to 20252681 its reverse (18625202), we get a palindrome (38877883).

The spelling of 20252681 in words is "twenty million, two hundred fifty-two thousand, six hundred eighty-one".