331777681 has 2 divisors, whose sum is σ = 331777682. Its totient is φ = 331777680.

The previous prime is 331777679. The next prime is 331777687. The reversal of 331777681 is 186777133.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 323460225 + 8317456 = 17985^2 + 2884^2 .

It is an emirp because it is prime and its reverse (186777133) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 331777681 - 2¹ = 331777679 is a prime.

It is a super-2 number, since 2×331777681² = 220152859219475522, which contains 22 as substring.

Together with 331777679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (331777687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165888840 + 165888841.

It is an arithmetic number, because the mean of its divisors is an integer number (165888841).

Almost surely, 2^331777681 is an apocalyptic number.

It is an amenable number.

331777681 is a deficient number, since it is larger than the sum of its proper divisors (1).

331777681 is an equidigital number, since it uses as much as digits as its factorization.

331777681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 148176, while the sum is 43.

The square root of 331777681 is about 18214.7654665110. The cubic root of 331777681 is about 692.2809629303.

The spelling of 331777681 in words is "three hundred thirty-one million, seven hundred seventy-seven thousand, six hundred eighty-one".