499906821 has 4 divisors (see below), whose sum is σ = 666542432. Its totient is φ = 333271212.

The previous prime is 499906801. The next prime is 499906861. The reversal of 499906821 is 128609994.

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 de Polignac number, because none of the positive numbers 2^k-499906821 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 (499906801) 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, 83317801 + ... + 83317806.

It is an arithmetic number, because the mean of its divisors is an integer number (166635608).

Almost surely, 2^499906821 is an apocalyptic number.

It is an amenable number.

499906821 is a deficient number, since it is larger than the sum of its proper divisors (166635611).

499906821 is a wasteful number, since it uses less digits than its factorization.

499906821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166635610.

The product of its (nonzero) digits is 279936, while the sum is 48.

The square root of 499906821 is about 22358.5961321367. The cubic root of 499906821 is about 793.6512187735.

The spelling of 499906821 in words is "four hundred ninety-nine million, nine hundred six thousand, eight hundred twenty-one".