172111720 has 32 divisors (see below), whose sum is σ = 422457120. Its totient is φ = 62585920.

The previous prime is 172111631. The next prime is 172111729. The reversal of 172111720 is 27111271.

It is a super-2 number, since 2×172111720² = 59244888322716800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a junction number, because it is equal to n+sod(n) for n = 172111691 and 172111700.

It is not an unprimeable number, because it can be changed into a prime (172111729) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 195142 + ... + 196021.

It is an arithmetic number, because the mean of its divisors is an integer number (13201785).

Almost surely, 2^172111720 is an apocalyptic number.

172111720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

172111720 is an abundant number, since it is smaller than the sum of its proper divisors (250345400).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

172111720 is a wasteful number, since it uses less digits than its factorization.

172111720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 391185 (or 391181 counting only the distinct ones).

The product of its (nonzero) digits is 196, while the sum is 22.

The square root of 172111720 is about 13119.1356422594. The cubic root of 172111720 is about 556.2501591549.

Adding to 172111720 its reverse (27111271), we get a palindrome (199222991).

The spelling of 172111720 in words is "one hundred seventy-two million, one hundred eleven thousand, seven hundred twenty".