398878207991 has 2 divisors, whose sum is σ = 398878207992. Its totient is φ = 398878207990.

The previous prime is 398878207979. The next prime is 398878208011. The reversal of 398878207991 is 199702878893.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 398878207991 - 2¹⁸ = 398877945847 is a prime.

It is a super-2 number, since 2×398878207991² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (398878207591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199439103995 + 199439103996.

It is an arithmetic number, because the mean of its divisors is an integer number (199439103996).

Almost surely, 2^398878207991 is an apocalyptic number.

398878207991 is a deficient number, since it is larger than the sum of its proper divisors (1).

398878207991 is an equidigital number, since it uses as much as digits as its factorization.

398878207991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 109734912, while the sum is 71.

The spelling of 398878207991 in words is "three hundred ninety-eight billion, eight hundred seventy-eight million, two hundred seven thousand, nine hundred ninety-one".