21121311047 has 2 divisors, whose sum is σ = 21121311048. Its totient is φ = 21121311046.

The previous prime is 21121311017. The next prime is 21121311053. The reversal of 21121311047 is 74011312112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21121311047 - 2¹⁶ = 21121245511 is a prime.

It is a super-2 number, since 2×21121311047² (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 (21121311017) 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, 10560655523 + 10560655524.

It is an arithmetic number, because the mean of its divisors is an integer number (10560655524).

Almost surely, 2^21121311047 is an apocalyptic number.

21121311047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121311047 is an equidigital number, since it uses as much as digits as its factorization.

21121311047 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 23.

Adding to 21121311047 its reverse (74011312112), we get a palindrome (95132623159).

The spelling of 21121311047 in words is "twenty-one billion, one hundred twenty-one million, three hundred eleven thousand, forty-seven".