20881331 has 2 divisors, whose sum is σ = 20881332. Its totient is φ = 20881330.

The previous prime is 20881319. The next prime is 20881349. The reversal of 20881331 is 13318802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20881331 - 2¹⁴ = 20864947 is a prime.

It is a super-2 number, since 2×20881331² = 872059968663122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20881331.

It is not a weakly prime, because it can be changed into another prime (20881381) 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 as a sum of consecutive naturals, namely, 10440665 + 10440666.

It is an arithmetic number, because the mean of its divisors is an integer number (10440666).

Almost surely, 2^20881331 is an apocalyptic number.

20881331 is a deficient number, since it is larger than the sum of its proper divisors (1).

20881331 is an equidigital number, since it uses as much as digits as its factorization.

20881331 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 20881331 is about 4569.6095019159. The cubic root of 20881331 is about 275.3717550727.

It can be divided in two parts, 20881 and 331, that added together give a palindrome (21212).

The spelling of 20881331 in words is "twenty million, eight hundred eighty-one thousand, three hundred thirty-one".