6720870857 has 4 divisors (see below), whose sum is σ = 6722590596. Its totient is φ = 6719151120.

The previous prime is 6720870841. The next prime is 6720870859. The reversal of 6720870857 is 7580780276.

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 3984639376 + 2736231481 = 63124^2 + 52309^2 .

It is a cyclic number.

It is not a de Polignac number, because 6720870857 - 2⁴ = 6720870841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6720870859) 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, 853994 + ... + 861827.

It is an arithmetic number, because the mean of its divisors is an integer number (1680647649).

Almost surely, 2^6720870857 is an apocalyptic number.

It is an amenable number.

6720870857 is a deficient number, since it is larger than the sum of its proper divisors (1719739).

6720870857 is a wasteful number, since it uses less digits than its factorization.

6720870857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1719738.

The product of its (nonzero) digits is 1317120, while the sum is 50.

The square root of 6720870857 is about 81980.9176394117. The cubic root of 6720870857 is about 1887.1591052093.

The spelling of 6720870857 in words is "six billion, seven hundred twenty million, eight hundred seventy thousand, eight hundred fifty-seven".