1601307781 has 2 divisors, whose sum is σ = 1601307782. Its totient is φ = 1601307780.

The previous prime is 1601307739. The next prime is 1601307787. The reversal of 1601307781 is 1877031061.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1187836225 + 413471556 = 34465^2 + 20334^2 .

It is a cyclic number.

It is not a de Polignac number, because 1601307781 - 2⁹ = 1601307269 is a prime.

It is a super-2 number, since 2×1601307781² = 5128373218982287922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1601307787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 800653890 + 800653891.

It is an arithmetic number, because the mean of its divisors is an integer number (800653891).

Almost surely, 2^1601307781 is an apocalyptic number.

It is an amenable number.

1601307781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1601307781 is an equidigital number, since it uses as much as digits as its factorization.

1601307781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7056, while the sum is 34.

The square root of 1601307781 is about 40016.3439234521. The cubic root of 1601307781 is about 1169.9256730731.

The spelling of 1601307781 in words is "one billion, six hundred one million, three hundred seven thousand, seven hundred eighty-one".