21201109847839 has 2 divisors, whose sum is σ = 21201109847840. Its totient is φ = 21201109847838.

The previous prime is 21201109847821. The next prime is 21201109847969. The reversal of 21201109847839 is 93874890110212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21201109847839 - 2¹¹ = 21201109845791 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21201109847839.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21201109841839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10600554923919 + 10600554923920.

It is an arithmetic number, because the mean of its divisors is an integer number (10600554923920).

Almost surely, 2^{21201109847839} is an apocalyptic number.

21201109847839 is a deficient number, since it is larger than the sum of its proper divisors (1).

21201109847839 is an equidigital number, since it uses as much as digits as its factorization.

21201109847839 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1741824, while the sum is 55.

The spelling of 21201109847839 in words is "twenty-one trillion, two hundred one billion, one hundred nine million, eight hundred forty-seven thousand, eight hundred thirty-nine".