972216172221 has 16 divisors (see below), whose sum is σ = 1481490589824. Its totient is φ = 555545225664.

The previous prime is 972216172201. The next prime is 972216172253. The reversal of 972216172221 is 122271612279.

It is not a de Polignac number, because 972216172221 - 2²¹ = 972214075069 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (972216172201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1807671 + ... + 2283003.

It is an arithmetic number, because the mean of its divisors is an integer number (92593161864).

Almost surely, 2^972216172221 is an apocalyptic number.

It is an amenable number.

972216172221 is a deficient number, since it is larger than the sum of its proper divisors (509274417603).

972216172221 is a wasteful number, since it uses less digits than its factorization.

972216172221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 572740.

The product of its digits is 84672, while the sum is 42.

The spelling of 972216172221 in words is "nine hundred seventy-two billion, two hundred sixteen million, one hundred seventy-two thousand, two hundred twenty-one".