396499991 has 2 divisors, whose sum is σ = 396499992. Its totient is φ = 396499990.

The previous prime is 396499981. The next prime is 396500009. The reversal of 396499991 is 199994693.

It is a weak prime.

It is an emirp because it is prime and its reverse (199994693) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-396499991 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 396499991.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (396499981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 198249995 + 198249996.

It is an arithmetic number, because the mean of its divisors is an integer number (198249996).

Almost surely, 2^396499991 is an apocalyptic number.

396499991 is a deficient number, since it is larger than the sum of its proper divisors (1).

396499991 is an equidigital number, since it uses as much as digits as its factorization.

396499991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4251528, while the sum is 59.

The square root of 396499991 is about 19912.3075257490. The cubic root of 396499991 is about 734.6509771769.

The spelling of 396499991 in words is "three hundred ninety-six million, four hundred ninety-nine thousand, nine hundred ninety-one".