6855552492721 has 9 divisors (see below), whose sum is σ = 6864148696171. Its totient is φ = 6846967050952.

The previous prime is 6855552492647. The next prime is 6855552492727. The reversal of 6855552492721 is 1272942555586.

The square root of 6855552492721 is 2618311.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 6775895333025 + 79657159696 = 2603055^2 + 282236^2 .

It is not a de Polignac number, because 6855552492721 - 2¹⁵ = 6855552459953 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 6855552492721.

It is not an unprimeable number, because it can be changed into a prime (6855552492727) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3594940050 + ... + 3594941956.

Almost surely, 2^{6855552492721} is an apocalyptic number.

6855552492721 is the 2618311-st square number.

6855552492721 is the 1309156-th centered octagonal number.

It is an amenable number.

6855552492721 is a deficient number, since it is larger than the sum of its proper divisors (8596203450).

6855552492721 is an frugal number, since it uses more digits than its factorization.

6855552492721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6560 (or 3280 counting only the distinct ones).

The product of its digits is 60480000, while the sum is 61.

The spelling of 6855552492721 in words is "six trillion, eight hundred fifty-five billion, five hundred fifty-two million, four hundred ninety-two thousand, seven hundred twenty-one".