6706857821 has 4 divisors (see below), whose sum is σ = 6748004352. Its totient is φ = 6665711292.

The previous prime is 6706857809. The next prime is 6706857847. The reversal of 6706857821 is 1287586076.

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 a de Polignac number, because none of the positive numbers 2^k-6706857821 is a prime.

It is a super-2 number, since 2×6706857821² = 89963883662217736082, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 6706857821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6706857851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20573021 + ... + 20573346.

It is an arithmetic number, because the mean of its divisors is an integer number (1687001088).

Almost surely, 2^6706857821 is an apocalyptic number.

It is an amenable number.

6706857821 is a deficient number, since it is larger than the sum of its proper divisors (41146531).

6706857821 is a wasteful number, since it uses less digits than its factorization.

6706857821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41146530.

The product of its (nonzero) digits is 1128960, while the sum is 50.

The square root of 6706857821 is about 81895.4078138695. The cubic root of 6706857821 is about 1885.8466151296.

The spelling of 6706857821 in words is "six billion, seven hundred six million, eight hundred fifty-seven thousand, eight hundred twenty-one".