820856667 has 4 divisors (see below), whose sum is σ = 1094475560. Its totient is φ = 547237776.

The previous prime is 820856609. The next prime is 820856681. The reversal of 820856667 is 766658028.

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

It is not a de Polignac number, because 820856667 - 2¹⁴ = 820840283 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820856567) 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, 136809442 + ... + 136809447.

It is an arithmetic number, because the mean of its divisors is an integer number (273618890).

Almost surely, 2^820856667 is an apocalyptic number.

820856667 is a deficient number, since it is larger than the sum of its proper divisors (273618893).

820856667 is a wasteful number, since it uses less digits than its factorization.

820856667 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 273618892.

The product of its (nonzero) digits is 967680, while the sum is 48.

The square root of 820856667 is about 28650.5962765175. The cubic root of 820856667 is about 936.3159967928.

The spelling of 820856667 in words is "eight hundred twenty million, eight hundred fifty-six thousand, six hundred sixty-seven".