351664681 has 2 divisors, whose sum is σ = 351664682. Its totient is φ = 351664680.

The previous prime is 351664679. The next prime is 351664697. The reversal of 351664681 is 186466153.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 344288025 + 7376656 = 18555^2 + 2716^2 .

It is a cyclic number.

It is not a de Polignac number, because 351664681 - 2¹ = 351664679 is a prime.

It is a super-4 number, since 4×351664681⁴ (a number of 35 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

Together with 351664679, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (351664981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 175832340 + 175832341.

It is an arithmetic number, because the mean of its divisors is an integer number (175832341).

Almost surely, 2^351664681 is an apocalyptic number.

It is an amenable number.

351664681 is a deficient number, since it is larger than the sum of its proper divisors (1).

351664681 is an equidigital number, since it uses as much as digits as its factorization.

351664681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 103680, while the sum is 40.

The square root of 351664681 is about 18752.7246287040. The cubic root of 351664681 is about 705.8453926390.

The spelling of 351664681 in words is "three hundred fifty-one million, six hundred sixty-four thousand, six hundred eighty-one".