21120720171 has 8 divisors (see below), whose sum is σ = 28161713664. Its totient is φ = 14080103400.

The previous prime is 21120720157. The next prime is 21120720191. The reversal of 21120720171 is 17102702112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21120720171 - 2⁵ = 21120720139 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21120720191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85746 + ... + 222696.

It is an arithmetic number, because the mean of its divisors is an integer number (3520214208).

Almost surely, 2^21120720171 is an apocalyptic number.

21120720171 is a deficient number, since it is larger than the sum of its proper divisors (7040993493).

21120720171 is a wasteful number, since it uses less digits than its factorization.

21120720171 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188361.

The product of its (nonzero) digits is 392, while the sum is 24.

The spelling of 21120720171 in words is "twenty-one billion, one hundred twenty million, seven hundred twenty thousand, one hundred seventy-one".