172391220 has 192 divisors, whose sum is σ = 576979200. Its totient is φ = 42577920.

The previous prime is 172391207. The next prime is 172391221. The reversal of 172391220 is 22193271.

172391220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172391221) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 816915 + ... + 817125.

It is an arithmetic number, because the mean of its divisors is an integer number (3005100).

Almost surely, 2^172391220 is an apocalyptic number.

172391220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 172391220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (288489600).

172391220 is an abundant number, since it is smaller than the sum of its proper divisors (404587980).

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

172391220 is a wasteful number, since it uses less digits than its factorization.

172391220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335 (or 327 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 172391220 is about 13129.7836996654. The cubic root of 172391220 is about 556.5511028986.

The spelling of 172391220 in words is "one hundred seventy-two million, three hundred ninety-one thousand, two hundred twenty".