20888381 has 4 divisors (see below), whose sum is σ = 21608700. Its totient is φ = 20168064.

The previous prime is 20888377. The next prime is 20888383. The reversal of 20888381 is 18388802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18388802 = 2 ⋅9194401.

It can be written as a sum of positive squares in 2 ways, for example, as 11222500 + 9665881 = 3350^2 + 3109^2 .

It is a cyclic number.

It is not a de Polignac number, because 20888381 - 2² = 20888377 is a prime.

It is a super-2 number, since 2×20888381² = 872648921602322, 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 (20888383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 360116 + ... + 360173.

It is an arithmetic number, because the mean of its divisors is an integer number (5402175).

Almost surely, 2^20888381 is an apocalyptic number.

It is an amenable number.

20888381 is a deficient number, since it is larger than the sum of its proper divisors (720319).

20888381 is an equidigital number, since it uses as much as digits as its factorization.

20888381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 720318.

The product of its (nonzero) digits is 24576, while the sum is 38.

The square root of 20888381 is about 4570.3808375233. The cubic root of 20888381 is about 275.4027421209.

The spelling of 20888381 in words is "twenty million, eight hundred eighty-eight thousand, three hundred eighty-one".