221688720172 has 24 divisors (see below), whose sum is σ = 388376513280. Its totient is φ = 110724069120.

The previous prime is 221688720151. The next prime is 221688720191. The reversal of 221688720172 is 271027886122.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18169578 + ... + 18181774.

It is an arithmetic number, because the mean of its divisors is an integer number (16182354720).

Almost surely, 2^221688720172 is an apocalyptic number.

It is an amenable number.

221688720172 is a deficient number, since it is larger than the sum of its proper divisors (166687793108).

221688720172 is a wasteful number, since it uses less digits than its factorization.

221688720172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16761 (or 16759 counting only the distinct ones).

The product of its (nonzero) digits is 301056, while the sum is 46.

The spelling of 221688720172 in words is "two hundred twenty-one billion, six hundred eighty-eight million, seven hundred twenty thousand, one hundred seventy-two".