21000011047 has 2 divisors, whose sum is σ = 21000011048. Its totient is φ = 21000011046.

The previous prime is 21000011029. The next prime is 21000011051. The reversal of 21000011047 is 74011000012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21000011047 - 2³¹ = 18852527399 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21000011047.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000011027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500005523 + 10500005524.

It is an arithmetic number, because the mean of its divisors is an integer number (10500005524).

Almost surely, 2^21000011047 is an apocalyptic number.

21000011047 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000011047 is an equidigital number, since it uses as much as digits as its factorization.

21000011047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 56, while the sum is 16.

Adding to 21000011047 its reverse (74011000012), we get a palindrome (95011011059).

The spelling of 21000011047 in words is "twenty-one billion, eleven thousand, forty-seven".