19701723707849 has 2 divisors, whose sum is σ = 19701723707850. Its totient is φ = 19701723707848.

The previous prime is 19701723707807. The next prime is 19701723707867. The reversal of 19701723707849 is 94870732710791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10470608732224 + 9231114975625 = 3235832^2 + 3038275^2 .

It is an emirp because it is prime and its reverse (94870732710791) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19701723707849 - 2⁸ = 19701723707593 is a prime.

It is not a weakly prime, because it can be changed into another prime (19701723707249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9850861853924 + 9850861853925.

It is an arithmetic number, because the mean of its divisors is an integer number (9850861853925).

Almost surely, 2^{19701723707849} is an apocalyptic number.

It is an amenable number.

19701723707849 is a deficient number, since it is larger than the sum of its proper divisors (1).

19701723707849 is an equidigital number, since it uses as much as digits as its factorization.

19701723707849 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 37340352, while the sum is 65.

The spelling of 19701723707849 in words is "nineteen trillion, seven hundred one billion, seven hundred twenty-three million, seven hundred seven thousand, eight hundred forty-nine".