20144981 has 4 divisors (see below), whose sum is σ = 20636364. Its totient is φ = 19653600.

The previous prime is 20144977. The next prime is 20144989. The reversal of 20144981 is 18944102.

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 2588881 + 17556100 = 1609^2 + 4190^2 .

It is a cyclic number.

It is not a de Polignac number, because 20144981 - 2² = 20144977 is a prime.

It is a super-2 number, since 2×20144981² = 811640518980722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20144989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 245630 + ... + 245711.

It is an arithmetic number, because the mean of its divisors is an integer number (5159091).

Almost surely, 2^20144981 is an apocalyptic number.

It is an amenable number.

20144981 is a deficient number, since it is larger than the sum of its proper divisors (491383).

20144981 is an equidigital number, since it uses as much as digits as its factorization.

20144981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 491382.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 20144981 is about 4488.3160539338. The cubic root of 20144981 is about 272.0960814324.

The spelling of 20144981 in words is "twenty million, one hundred forty-four thousand, nine hundred eighty-one".