20001081 has 4 divisors (see below), whose sum is σ = 26668112. Its totient is φ = 13334052.

The previous prime is 20001073. The next prime is 20001083. The reversal of 20001081 is 18010002.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20001081 - 2³ = 20001073 is a prime.

It is a super-2 number, since 2×20001081² = 800086482337122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20001083) 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 in 3 ways as a sum of consecutive naturals, for example, 3333511 + ... + 3333516.

It is an arithmetic number, because the mean of its divisors is an integer number (6667028).

Almost surely, 2^20001081 is an apocalyptic number.

It is an amenable number.

20001081 is a deficient number, since it is larger than the sum of its proper divisors (6667031).

20001081 is an equidigital number, since it uses as much as digits as its factorization.

20001081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6667030.

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 20001081 is about 4472.2568128407. The cubic root of 20001081 is about 271.4466520471.

Adding to 20001081 its reverse (18010002), we get a palindrome (38011083).

It can be divided in two parts, 2000 and 1081, that added together give a triangular number (3081 = T₇₈).

The spelling of 20001081 in words is "twenty million, one thousand, eighty-one".