72170555321 has 2 divisors, whose sum is σ = 72170555322. Its totient is φ = 72170555320.

The previous prime is 72170555291. The next prime is 72170555333. The reversal of 72170555321 is 12355507127.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 45811409296 + 26359146025 = 214036^2 + 162355^2 .

It is a cyclic number.

It is not a de Polignac number, because 72170555321 - 2⁶ = 72170555257 is a prime.

It is not a weakly prime, because it can be changed into another prime (72170555341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36085277660 + 36085277661.

It is an arithmetic number, because the mean of its divisors is an integer number (36085277661).

Almost surely, 2^72170555321 is an apocalyptic number.

It is an amenable number.

72170555321 is a deficient number, since it is larger than the sum of its proper divisors (1).

72170555321 is an equidigital number, since it uses as much as digits as its factorization.

72170555321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 73500, while the sum is 38.

The spelling of 72170555321 in words is "seventy-two billion, one hundred seventy million, five hundred fifty-five thousand, three hundred twenty-one".