398666869 has 2 divisors, whose sum is σ = 398666870. Its totient is φ = 398666868.

The previous prime is 398666837. The next prime is 398666887. The reversal of 398666869 is 968666893.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 387577969 + 11088900 = 19687^2 + 3330^2 .

It is a cyclic number.

It is not a de Polignac number, because 398666869 - 2⁵ = 398666837 is a prime.

It is a super-2 number, since 2×398666869² = 317870544876526322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (398666069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199333434 + 199333435.

It is an arithmetic number, because the mean of its divisors is an integer number (199333435).

Almost surely, 2^398666869 is an apocalyptic number.

It is an amenable number.

398666869 is a deficient number, since it is larger than the sum of its proper divisors (1).

398666869 is an equidigital number, since it uses as much as digits as its factorization.

398666869 is an evil number, because the sum of its binary digits is even.

The product of its digits is 20155392, while the sum is 61.

The square root of 398666869 is about 19966.6439092803. The cubic root of 398666869 is about 735.9868392466.

The spelling of 398666869 in words is "three hundred ninety-eight million, six hundred sixty-six thousand, eight hundred sixty-nine".