381840856409 has 2 divisors, whose sum is σ = 381840856410. Its totient is φ = 381840856408.

The previous prime is 381840856381. The next prime is 381840856421. The reversal of 381840856409 is 904658048183.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 304527385600 + 77313470809 = 551840^2 + 278053^2 .

It is a cyclic number.

It is not a de Polignac number, because 381840856409 - 2²⁸ = 381572420953 is a prime.

It is not a weakly prime, because it can be changed into another prime (381840856469) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 190920428204 + 190920428205.

It is an arithmetic number, because the mean of its divisors is an integer number (190920428205).

Almost surely, 2^381840856409 is an apocalyptic number.

It is an amenable number.

381840856409 is a deficient number, since it is larger than the sum of its proper divisors (1).

381840856409 is an equidigital number, since it uses as much as digits as its factorization.

381840856409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6635520, while the sum is 56.

The spelling of 381840856409 in words is "three hundred eighty-one billion, eight hundred forty million, eight hundred fifty-six thousand, four hundred nine".