1781310161 has 2 divisors, whose sum is σ = 1781310162. Its totient is φ = 1781310160.

The previous prime is 1781310107. The next prime is 1781310197. The reversal of 1781310161 is 1610131871.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1659340225 + 121969936 = 40735^2 + 11044^2 .

It is an emirp because it is prime and its reverse (1610131871) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1781310161 - 2¹⁴ = 1781293777 is a prime.

It is not a weakly prime, because it can be changed into another prime (1781310101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 890655080 + 890655081.

It is an arithmetic number, because the mean of its divisors is an integer number (890655081).

Almost surely, 2^1781310161 is an apocalyptic number.

It is an amenable number.

1781310161 is a deficient number, since it is larger than the sum of its proper divisors (1).

1781310161 is an equidigital number, since it uses as much as digits as its factorization.

1781310161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1008, while the sum is 29.

The square root of 1781310161 is about 42205.5702603341. The cubic root of 1781310161 is about 1212.2155435163.

The spelling of 1781310161 in words is "one billion, seven hundred eighty-one million, three hundred ten thousand, one hundred sixty-one".