21121320071 has 2 divisors, whose sum is σ = 21121320072. Its totient is φ = 21121320070.

The previous prime is 21121320001. The next prime is 21121320091. The reversal of 21121320071 is 17002312112.

It is an a-pointer prime, because the next prime (21121320091) can be obtained adding 21121320071 to its sum of digits (20).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21121320071 - 2¹⁰ = 21121319047 is a prime.

It is a super-2 number, since 2×21121320071² (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 (21121320001) 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, 10560660035 + 10560660036.

It is an arithmetic number, because the mean of its divisors is an integer number (10560660036).

Almost surely, 2^21121320071 is an apocalyptic number.

21121320071 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121320071 is an equidigital number, since it uses as much as digits as its factorization.

21121320071 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 168, while the sum is 20.

Adding to 21121320071 its reverse (17002312112), we get a palindrome (38123632183).

The spelling of 21121320071 in words is "twenty-one billion, one hundred twenty-one million, three hundred twenty thousand, seventy-one".