331661641 has 2 divisors, whose sum is σ = 331661642. Its totient is φ = 331661640.

The previous prime is 331661639. The next prime is 331661677. The reversal of 331661641 is 146166133.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 176783616 + 154878025 = 13296^2 + 12445^2 .

It is an emirp because it is prime and its reverse (146166133) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 331661641 - 2¹ = 331661639 is a prime.

It is a super-2 number, since 2×331661641² = 219998888221625762, which contains 22 as substring.

Together with 331661639, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (331661621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165830820 + 165830821.

It is an arithmetic number, because the mean of its divisors is an integer number (165830821).

Almost surely, 2^331661641 is an apocalyptic number.

It is an amenable number.

331661641 is a deficient number, since it is larger than the sum of its proper divisors (1).

331661641 is an equidigital number, since it uses as much as digits as its factorization.

331661641 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 31.

The square root of 331661641 is about 18211.5798600780. The cubic root of 331661641 is about 692.2002445710.

The spelling of 331661641 in words is "three hundred thirty-one million, six hundred sixty-one thousand, six hundred forty-one".