21121101247 has 2 divisors, whose sum is σ = 21121101248. Its totient is φ = 21121101246.

The previous prime is 21121101173. The next prime is 21121101263. The reversal of 21121101247 is 74210112112.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21121101247 - 2¹¹ = 21121099199 is a prime.

It is a super-2 number, since 2×21121101247² (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 (21121101647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560550623 + 10560550624.

It is an arithmetic number, because the mean of its divisors is an integer number (10560550624).

Almost surely, 2^21121101247 is an apocalyptic number.

21121101247 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121101247 is an equidigital number, since it uses as much as digits as its factorization.

21121101247 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 224, while the sum is 22.

Adding to 21121101247 its reverse (74210112112), we get a palindrome (95331213359).

The spelling of 21121101247 in words is "twenty-one billion, one hundred twenty-one million, one hundred one thousand, two hundred forty-seven".