21191847139 has 2 divisors, whose sum is σ = 21191847140. Its totient is φ = 21191847138.

The previous prime is 21191847137. The next prime is 21191847289. The reversal of 21191847139 is 93174819112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21191847139 - 2¹ = 21191847137 is a prime.

Together with 21191847137, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21191847137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10595923569 + 10595923570.

It is an arithmetic number, because the mean of its divisors is an integer number (10595923570).

Almost surely, 2^21191847139 is an apocalyptic number.

21191847139 is a deficient number, since it is larger than the sum of its proper divisors (1).

21191847139 is an equidigital number, since it uses as much as digits as its factorization.

21191847139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108864, while the sum is 46.

The spelling of 21191847139 in words is "twenty-one billion, one hundred ninety-one million, eight hundred forty-seven thousand, one hundred thirty-nine".