21110381 has 2 divisors, whose sum is σ = 21110382. Its totient is φ = 21110380.

The previous prime is 21110363. The next prime is 21110393. The reversal of 21110381 is 18301112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12460900 + 8649481 = 3530^2 + 2941^2 .

It is a cyclic number.

It is not a de Polignac number, because 21110381 - 2¹⁴ = 21093997 is a prime.

It is a super-2 number, since 2×21110381² = 891296371930322, 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 (21110981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555190 + 10555191.

It is an arithmetic number, because the mean of its divisors is an integer number (10555191).

Almost surely, 2^21110381 is an apocalyptic number.

It is an amenable number.

21110381 is a deficient number, since it is larger than the sum of its proper divisors (1).

21110381 is an equidigital number, since it uses as much as digits as its factorization.

21110381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 17.

The square root of 21110381 is about 4594.6034649358. The cubic root of 21110381 is about 276.3749585849.

Adding to 21110381 its reverse (18301112), we get a palindrome (39411493).

The spelling of 21110381 in words is "twenty-one million, one hundred ten thousand, three hundred eighty-one".