172205720 has 16 divisors (see below), whose sum is σ = 387462960. Its totient is φ = 68882272.

The previous prime is 172205717. The next prime is 172205723. The reversal of 172205720 is 27502271.

It is an interprime number because it is at equal distance from previous prime (172205717) and next prime (172205723).

It is a self number, because there is not a number n which added to its sum of digits gives 172205720.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172205723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2152532 + ... + 2152611.

It is an arithmetic number, because the mean of its divisors is an integer number (24216435).

Almost surely, 2^172205720 is an apocalyptic number.

172205720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

172205720 is an abundant number, since it is smaller than the sum of its proper divisors (215257240).

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

172205720 is a wasteful number, since it uses less digits than its factorization.

172205720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4305154 (or 4305150 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 26.

The square root of 172205720 is about 13122.7177063290. The cubic root of 172205720 is about 556.3514073418.

Adding to 172205720 its reverse (27502271), we get a palindrome (199707991).

The spelling of 172205720 in words is "one hundred seventy-two million, two hundred five thousand, seven hundred twenty".