20144581 has 4 divisors (see below), whose sum is σ = 20153664. Its totient is φ = 20135500.

The previous prime is 20144557. The next prime is 20144587. The reversal of 20144581 is 18544102.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20144581 - 2⁵ = 20144549 is a prime.

It is a super-2 number, since 2×20144581² = 811608287331122, 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 (20144587) 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, 1236 + ... + 6466.

It is an arithmetic number, because the mean of its divisors is an integer number (5038416).

Almost surely, 2^20144581 is an apocalyptic number.

It is an amenable number.

20144581 is a deficient number, since it is larger than the sum of its proper divisors (9083).

20144581 is an equidigital number, since it uses as much as digits as its factorization.

20144581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9082.

The product of its (nonzero) digits is 1280, while the sum is 25.

The square root of 20144581 is about 4488.2714935708. The cubic root of 20144581 is about 272.0942805016.

Adding to 20144581 its reverse (18544102), we get a palindrome (38688683).

The spelling of 20144581 in words is "twenty million, one hundred forty-four thousand, five hundred eighty-one".