21115941440947 has 2 divisors, whose sum is σ = 21115941440948. Its totient is φ = 21115941440946.

The previous prime is 21115941440941. The next prime is 21115941440989. The reversal of 21115941440947 is 74904414951112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21115941440947 - 2³ = 21115941440939 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21115941440894 and 21115941440903.

It is not a weakly prime, because it can be changed into another prime (21115941440941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10557970720473 + 10557970720474.

It is an arithmetic number, because the mean of its divisors is an integer number (10557970720474).

Almost surely, 2^{21115941440947} is an apocalyptic number.

21115941440947 is a deficient number, since it is larger than the sum of its proper divisors (1).

21115941440947 is an equidigital number, since it uses as much as digits as its factorization.

21115941440947 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1451520, while the sum is 52.

The spelling of 21115941440947 in words is "twenty-one trillion, one hundred fifteen billion, nine hundred forty-one million, four hundred forty thousand, nine hundred forty-seven".