21121100047 has 2 divisors, whose sum is σ = 21121100048. Its totient is φ = 21121100046.

The previous prime is 21121099991. The next prime is 21121100071. The reversal of 21121100047 is 74000112112.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21121100047 is a prime.

It is a super-2 number, since 2×21121100047² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121099997 and 21121100033.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21121100347) 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, 10560550023 + 10560550024.

It is an arithmetic number, because the mean of its divisors is an integer number (10560550024).

Almost surely, 2^21121100047 is an apocalyptic number.

21121100047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121100047 is an equidigital number, since it uses as much as digits as its factorization.

21121100047 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 112, while the sum is 19.

Adding to 21121100047 its reverse (74000112112), we get a palindrome (95121212159).

The spelling of 21121100047 in words is "twenty-one billion, one hundred twenty-one million, one hundred thousand, forty-seven".