8211666525 has 48 divisors (see below), whose sum is σ = 14492643840. Its totient is φ = 4090564800.

The previous prime is 8211666511. The next prime is 8211666571. The reversal of 8211666525 is 5256661128.

It is not a de Polignac number, because 8211666525 - 2⁶ = 8211666461 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 60594 + ... + 141756.

It is an arithmetic number, because the mean of its divisors is an integer number (301930080).

Almost surely, 2^8211666525 is an apocalyptic number.

It is an amenable number.

8211666525 is a deficient number, since it is larger than the sum of its proper divisors (6280977315).

8211666525 is a wasteful number, since it uses less digits than its factorization.

8211666525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81266 (or 81261 counting only the distinct ones).

The product of its digits is 172800, while the sum is 42.

The square root of 8211666525 is about 90618.2460931572. The cubic root of 8211666525 is about 2017.4855591835.

The spelling of 8211666525 in words is "eight billion, two hundred eleven million, six hundred sixty-six thousand, five hundred twenty-five".