172420321 has 4 divisors (see below), whose sum is σ = 172932292. Its totient is φ = 171908352.

The previous prime is 172420271. The next prime is 172420327. The reversal of 172420321 is 123024271.

172420321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 101203600 + 71216721 = 10060^2 + 8439^2 .

It is a cyclic number.

It is not a de Polignac number, because 172420321 - 2¹¹ = 172418273 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 172420292 and 172420301.

It is not an unprimeable number, because it can be changed into a prime (172420327) 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, 255480 + ... + 256153.

It is an arithmetic number, because the mean of its divisors is an integer number (43233073).

Almost surely, 2^172420321 is an apocalyptic number.

It is an amenable number.

172420321 is a deficient number, since it is larger than the sum of its proper divisors (511971).

172420321 is an equidigital number, since it uses as much as digits as its factorization.

172420321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 511970.

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 172420321 is about 13130.8918585144. The cubic root of 172420321 is about 556.5824178778.

Adding to 172420321 its reverse (123024271), we get a palindrome (295444592).

The spelling of 172420321 in words is "one hundred seventy-two million, four hundred twenty thousand, three hundred twenty-one".