1947117967021 has 2 divisors, whose sum is σ = 1947117967022. Its totient is φ = 1947117967020.

The previous prime is 1947117967001. The next prime is 1947117967033. The reversal of 1947117967021 is 1207697117491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1499571684900 + 447546282121 = 1224570^2 + 668989^2 .

It is an emirp because it is prime and its reverse (1207697117491) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1947117967021 - 2⁹ = 1947117966509 is a prime.

It is a super-2 number, since 2×1947117967021² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1947117967001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 973558983510 + 973558983511.

It is an arithmetic number, because the mean of its divisors is an integer number (973558983511).

Almost surely, 2^{1947117967021} is an apocalyptic number.

It is an amenable number.

1947117967021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1947117967021 is an equidigital number, since it uses as much as digits as its factorization.

1947117967021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1333584, while the sum is 55.

The spelling of 1947117967021 in words is "one trillion, nine hundred forty-seven billion, one hundred seventeen million, nine hundred sixty-seven thousand, twenty-one".