7872171336121 has 9 divisors (see below), whose sum is σ = 7887630350383. Its totient is φ = 7856742577360.

The previous prime is 7872171336109. The next prime is 7872171336163. The reversal of 7872171336121 is 1216331712787.

The square root of 7872171336121 is 2805739.

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., 1297459961721 + 6574711374400 = 1139061^2 + 2564120^2 .

It is not a de Polignac number, because 7872171336121 - 2¹³ = 7872171327929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7872171336221) 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, 1596463026 + ... + 1596467956.

Almost surely, 2^{7872171336121} is an apocalyptic number.

7872171336121 is the 2805739-th square number.

7872171336121 is the 1402870-th centered octagonal number.

It is an amenable number.

7872171336121 is a deficient number, since it is larger than the sum of its proper divisors (15459014262).

7872171336121 is an frugal number, since it uses more digits than its factorization.

7872171336121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11000 (or 5500 counting only the distinct ones).

The product of its digits is 592704, while the sum is 49.

Multiplying 7872171336121 by its sum of digits (49), we get a square (385736395469929 = 19640173²).

The spelling of 7872171336121 in words is "seven trillion, eight hundred seventy-two billion, one hundred seventy-one million, three hundred thirty-six thousand, one hundred twenty-one".