404878993 has 4 divisors (see below), whose sum is σ = 407219508. Its totient is φ = 402538480.

The previous prime is 404878963. The next prime is 404878997. The reversal of 404878993 is 399878404.

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 391129729 + 13749264 = 19777^2 + 3708^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-404878993 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 404878993.

It is not an unprimeable number, because it can be changed into a prime (404878997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1169998 + ... + 1170343.

It is an arithmetic number, because the mean of its divisors is an integer number (101804877).

Almost surely, 2^404878993 is an apocalyptic number.

It is an amenable number.

404878993 is a deficient number, since it is larger than the sum of its proper divisors (2340515).

404878993 is a wasteful number, since it uses less digits than its factorization.

404878993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2340514.

The product of its (nonzero) digits is 1741824, while the sum is 52.

The square root of 404878993 is about 20121.6051298101. The cubic root of 404878993 is about 739.7899288050.

The spelling of 404878993 in words is "four hundred four million, eight hundred seventy-eight thousand, nine hundred ninety-three".