21147994313 has 2 divisors, whose sum is σ = 21147994314. Its totient is φ = 21147994312.

The previous prime is 21147994261. The next prime is 21147994321. The reversal of 21147994313 is 31349974112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19290987664 + 1857006649 = 138892^2 + 43093^2 .

It is a cyclic number.

It is not a de Polignac number, because 21147994313 - 2⁸ = 21147994057 is a prime.

It is not a weakly prime, because it can be changed into another prime (21147994363) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10573997156 + 10573997157.

It is an arithmetic number, because the mean of its divisors is an integer number (10573997157).

Almost surely, 2^21147994313 is an apocalyptic number.

It is an amenable number.

21147994313 is a deficient number, since it is larger than the sum of its proper divisors (1).

21147994313 is an equidigital number, since it uses as much as digits as its factorization.

21147994313 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 44.

It can be divided in two parts, 2114799 and 4313, that added together give a palindrome (2119112).

The spelling of 21147994313 in words is "twenty-one billion, one hundred forty-seven million, nine hundred ninety-four thousand, three hundred thirteen".