398421505 has 4 divisors (see below), whose sum is σ = 478105812. Its totient is φ = 318737200.

The previous prime is 398421493. The next prime is 398421509. The reversal of 398421505 is 505124893.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 45319824 + 353101681 = 6732^2 + 18791^2 .

It is not a de Polignac number, because 398421505 - 2⁵ = 398421473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (398421509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39842146 + ... + 39842155.

It is an arithmetic number, because the mean of its divisors is an integer number (119526453).

Almost surely, 2^398421505 is an apocalyptic number.

It is an amenable number.

398421505 is a deficient number, since it is larger than the sum of its proper divisors (79684307).

398421505 is an equidigital number, since it uses as much as digits as its factorization.

398421505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79684306.

The product of its (nonzero) digits is 43200, while the sum is 37.

The square root of 398421505 is about 19960.4986160166. The cubic root of 398421505 is about 735.8358178056.

The spelling of 398421505 in words is "three hundred ninety-eight million, four hundred twenty-one thousand, five hundred five".