6404042821 has 4 divisors (see below), whose sum is σ = 6986228544. Its totient is φ = 5821857100.

The previous prime is 6404042809. The next prime is 6404042831. The reversal of 6404042821 is 1282404046.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6404042821 - 2¹⁷ = 6403911749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6404042831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 291092845 + ... + 291092866.

It is an arithmetic number, because the mean of its divisors is an integer number (1746557136).

Almost surely, 2^6404042821 is an apocalyptic number.

It is an amenable number.

6404042821 is a deficient number, since it is larger than the sum of its proper divisors (582185723).

6404042821 is a wasteful number, since it uses less digits than its factorization.

6404042821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 582185722.

The product of its (nonzero) digits is 12288, while the sum is 31.

The square root of 6404042821 is about 80025.2636421774. The cubic root of 6404042821 is about 1857.0263910065.

Adding to 6404042821 its reverse (1282404046), we get a palindrome (7686446867).

The spelling of 6404042821 in words is "six billion, four hundred four million, forty-two thousand, eight hundred twenty-one".