172615321 has 2 divisors, whose sum is σ = 172615322. Its totient is φ = 172615320.

The previous prime is 172615307. The next prime is 172615327. The reversal of 172615321 is 123516271.

It is a happy number.

172615321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 155351296 + 17264025 = 12464^2 + 4155^2 .

It is a cyclic number.

It is not a de Polignac number, because 172615321 - 2⁷ = 172615193 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 172615321.

It is not a weakly prime, because it can be changed into another prime (172615327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86307660 + 86307661.

It is an arithmetic number, because the mean of its divisors is an integer number (86307661).

Almost surely, 2^172615321 is an apocalyptic number.

It is an amenable number.

172615321 is a deficient number, since it is larger than the sum of its proper divisors (1).

172615321 is an equidigital number, since it uses as much as digits as its factorization.

172615321 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2520, while the sum is 28.

The square root of 172615321 is about 13138.3149985072. The cubic root of 172615321 is about 556.7921624542.

The spelling of 172615321 in words is "one hundred seventy-two million, six hundred fifteen thousand, three hundred twenty-one".