21115000381 has 2 divisors, whose sum is σ = 21115000382. Its totient is φ = 21115000380.

The previous prime is 21115000373. The next prime is 21115000411. The reversal of 21115000381 is 18300051112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16315974756 + 4799025625 = 127734^2 + 69275^2 .

It is a cyclic number.

It is not a de Polignac number, because 21115000381 - 2³ = 21115000373 is a prime.

It is a super-2 number, since 2×21115000381² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21115000301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10557500190 + 10557500191.

It is an arithmetic number, because the mean of its divisors is an integer number (10557500191).

Almost surely, 2^21115000381 is an apocalyptic number.

It is an amenable number.

21115000381 is a deficient number, since it is larger than the sum of its proper divisors (1).

21115000381 is an equidigital number, since it uses as much as digits as its factorization.

21115000381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 240, while the sum is 22.

Adding to 21115000381 its reverse (18300051112), we get a palindrome (39415051493).

The spelling of 21115000381 in words is "twenty-one billion, one hundred fifteen million, three hundred eighty-one", and thus it is an aban number.