21341381 has 2 divisors, whose sum is σ = 21341382. Its totient is φ = 21341380.

The previous prime is 21341377. The next prime is 21341387. The reversal of 21341381 is 18314312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20205025 + 1136356 = 4495^2 + 1066^2 .

It is a cyclic number.

It is not a de Polignac number, because 21341381 - 2² = 21341377 is a prime.

It is a super-2 number, since 2×21341381² = 910909085974322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21341387) 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 as a sum of consecutive naturals, namely, 10670690 + 10670691.

It is an arithmetic number, because the mean of its divisors is an integer number (10670691).

Almost surely, 2^21341381 is an apocalyptic number.

It is an amenable number.

21341381 is a deficient number, since it is larger than the sum of its proper divisors (1).

21341381 is an equidigital number, since it uses as much as digits as its factorization.

21341381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 23.

The square root of 21341381 is about 4619.6732568440. The cubic root of 21341381 is about 277.3793799835.

Adding to 21341381 its reverse (18314312), we get a palindrome (39655693).

The spelling of 21341381 in words is "twenty-one million, three hundred forty-one thousand, three hundred eighty-one".