3557681 has 2 divisors, whose sum is σ = 3557682. Its totient is φ = 3557680.

The previous prime is 3557647. The next prime is 3557683. The reversal of 3557681 is 1867553.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3045025 + 512656 = 1745^2 + 716^2 .

It is an emirp because it is prime and its reverse (1867553) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 3557681 - 2¹⁴ = 3541297 is a prime.

It is a super-2 number, since 2×3557681² = 25314188195522, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 3557683, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (3557683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1778840 + 1778841.

It is an arithmetic number, because the mean of its divisors is an integer number (1778841).

Almost surely, 2^3557681 is an apocalyptic number.

It is an amenable number.

3557681 is a deficient number, since it is larger than the sum of its proper divisors (1).

3557681 is an equidigital number, since it uses as much as digits as its factorization.

3557681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25200, while the sum is 35.

The square root of 3557681 is about 1886.1815925303. The cubic root of 3557681 is about 152.6589724473.

The spelling of 3557681 in words is "three million, five hundred fifty-seven thousand, six hundred eighty-one".