21021131071 has 2 divisors, whose sum is σ = 21021131072. Its totient is φ = 21021131070.

The previous prime is 21021131069. The next prime is 21021131077. The reversal of 21021131071 is 17013112012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21021131071 - 2¹ = 21021131069 is a prime.

Together with 21021131069, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21021131077) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510565535 + 10510565536.

It is an arithmetic number, because the mean of its divisors is an integer number (10510565536).

Almost surely, 2^21021131071 is an apocalyptic number.

21021131071 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021131071 is an equidigital number, since it uses as much as digits as its factorization.

21021131071 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 84, while the sum is 19.

Adding to 21021131071 its reverse (17013112012), we get a palindrome (38034243083).

The spelling of 21021131071 in words is "twenty-one billion, twenty-one million, one hundred thirty-one thousand, seventy-one".