20275681 has 4 divisors (see below), whose sum is σ = 20297412. Its totient is φ = 20253952.

The previous prime is 20275663. The next prime is 20275687. The reversal of 20275681 is 18657202.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13432225 + 6843456 = 3665^2 + 2616^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20275681 is a prime.

It is a super-2 number, since 2×20275681² = 822206480027522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20275687) 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, 9400 + ... + 11353.

It is an arithmetic number, because the mean of its divisors is an integer number (5074353).

Almost surely, 2^20275681 is an apocalyptic number.

It is an amenable number.

20275681 is a deficient number, since it is larger than the sum of its proper divisors (21731).

20275681 is an equidigital number, since it uses as much as digits as its factorization.

20275681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21730.

The product of its (nonzero) digits is 6720, while the sum is 31.

The square root of 20275681 is about 4502.8525403348. The cubic root of 20275681 is about 272.6832636429.

The spelling of 20275681 in words is "twenty million, two hundred seventy-five thousand, six hundred eighty-one".