21402177712849 has 2 divisors, whose sum is σ = 21402177712850. Its totient is φ = 21402177712848.

The previous prime is 21402177712843. The next prime is 21402177712889. The reversal of 21402177712849 is 94821777120412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18201145038400 + 3201032674449 = 4266280^2 + 1789143^2 .

It is a cyclic number.

It is not a de Polignac number, because 21402177712849 - 2¹⁷ = 21402177581777 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21402177712849.

It is not a weakly prime, because it can be changed into another prime (21402177712843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10701088856424 + 10701088856425.

It is an arithmetic number, because the mean of its divisors is an integer number (10701088856425).

Almost surely, 2^{21402177712849} is an apocalyptic number.

It is an amenable number.

21402177712849 is a deficient number, since it is larger than the sum of its proper divisors (1).

21402177712849 is an equidigital number, since it uses as much as digits as its factorization.

21402177712849 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3161088, while the sum is 55.

The spelling of 21402177712849 in words is "twenty-one trillion, four hundred two billion, one hundred seventy-seven million, seven hundred twelve thousand, eight hundred forty-nine".