21172162000208 has 10 divisors (see below), whose sum is σ = 41021063875434. Its totient is φ = 10586081000096.

The previous prime is 21172162000201. The next prime is 21172162000313. The reversal of 21172162000208 is 80200026127112.

It can be written as a sum of positive squares in only one way, i.e., 16838154178624 + 4334007821584 = 4103432^2 + 2081828^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21172162000201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 661630062491 + ... + 661630062522.

Almost surely, 2^{21172162000208} is an apocalyptic number.

It is an amenable number.

21172162000208 is a deficient number, since it is larger than the sum of its proper divisors (19848901875226).

21172162000208 is a wasteful number, since it uses less digits than its factorization.

21172162000208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1323260125021 (or 1323260125015 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 32.

The spelling of 21172162000208 in words is "twenty-one trillion, one hundred seventy-two billion, one hundred sixty-two million, two hundred eight", and thus it is an aban number.