21000011100947 has 2 divisors, whose sum is σ = 21000011100948. Its totient is φ = 21000011100946.

The previous prime is 21000011100853. The next prime is 21000011100997. The reversal of 21000011100947 is 74900111000012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21000011100947 - 2³⁰ = 20998937359123 is a prime.

It is not a weakly prime, because it can be changed into another prime (21000011100997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500005550473 + 10500005550474.

It is an arithmetic number, because the mean of its divisors is an integer number (10500005550474).

Almost surely, 2^{21000011100947} is an apocalyptic number.

21000011100947 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000011100947 is an equidigital number, since it uses as much as digits as its factorization.

21000011100947 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 504, while the sum is 26.

Adding to 21000011100947 its reverse (74900111000012), we get a palindrome (95900122100959).

The spelling of 21000011100947 in words is "twenty-one trillion, eleven million, one hundred thousand, nine hundred forty-seven".