21311981027 has 2 divisors, whose sum is σ = 21311981028. Its totient is φ = 21311981026.

The previous prime is 21311980981. The next prime is 21311981057. The reversal of 21311981027 is 72018911312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21311981027 - 2⁸ = 21311980771 is a prime.

It is not a weakly prime, because it can be changed into another prime (21311981057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10655990513 + 10655990514.

It is an arithmetic number, because the mean of its divisors is an integer number (10655990514).

Almost surely, 2^21311981027 is an apocalyptic number.

21311981027 is a deficient number, since it is larger than the sum of its proper divisors (1).

21311981027 is an equidigital number, since it uses as much as digits as its factorization.

21311981027 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 35.

The spelling of 21311981027 in words is "twenty-one billion, three hundred eleven million, nine hundred eighty-one thousand, twenty-seven".