21131211047 has 2 divisors, whose sum is σ = 21131211048. Its totient is φ = 21131211046.

The previous prime is 21131210983. The next prime is 21131211053. The reversal of 21131211047 is 74011213112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21131211047 - 2⁶ = 21131210983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21131211077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565605523 + 10565605524.

It is an arithmetic number, because the mean of its divisors is an integer number (10565605524).

Almost surely, 2^21131211047 is an apocalyptic number.

21131211047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21131211047 is an equidigital number, since it uses as much as digits as its factorization.

21131211047 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 21131211047 its reverse (74011213112), we get a palindrome (95142424159).

The spelling of 21131211047 in words is "twenty-one billion, one hundred thirty-one million, two hundred eleven thousand, forty-seven".