407998991 has 2 divisors, whose sum is σ = 407998992. Its totient is φ = 407998990.

The previous prime is 407998949. The next prime is 407998993. The reversal of 407998991 is 199899704.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-407998991 is a prime.

Together with 407998993, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (407998993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 203999495 + 203999496.

It is an arithmetic number, because the mean of its divisors is an integer number (203999496).

Almost surely, 2^407998991 is an apocalyptic number.

407998991 is a deficient number, since it is larger than the sum of its proper divisors (1).

407998991 is an equidigital number, since it uses as much as digits as its factorization.

407998991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1469664, while the sum is 56.

The square root of 407998991 is about 20198.9849002369. The cubic root of 407998991 is about 741.6853424466.

The spelling of 407998991 in words is "four hundred seven million, nine hundred ninety-eight thousand, nine hundred ninety-one".