398261779 has 2 divisors, whose sum is σ = 398261780. Its totient is φ = 398261778.

The previous prime is 398261761. The next prime is 398261783. The reversal of 398261779 is 977162893.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 398261779 - 2¹⁵ = 398229011 is a prime.

It is a super-2 number, since 2×398261779² = 317224889224489682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (398261719) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199130889 + 199130890.

It is an arithmetic number, because the mean of its divisors is an integer number (199130890).

Almost surely, 2^398261779 is an apocalyptic number.

398261779 is a deficient number, since it is larger than the sum of its proper divisors (1).

398261779 is an equidigital number, since it uses as much as digits as its factorization.

398261779 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1143072, while the sum is 52.

The square root of 398261779 is about 19956.4971625784. The cubic root of 398261779 is about 735.7374731965.

The spelling of 398261779 in words is "three hundred ninety-eight million, two hundred sixty-one thousand, seven hundred seventy-nine".