172720447 has 2 divisors, whose sum is σ = 172720448. Its totient is φ = 172720446.

The previous prime is 172720423. The next prime is 172720451. The reversal of 172720447 is 744027271.

It is a happy number.

172720447 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 is a cyclic number.

It is not a de Polignac number, because 172720447 - 2⁷ = 172720319 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172721447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86360223 + 86360224.

It is an arithmetic number, because the mean of its divisors is an integer number (86360224).

Almost surely, 2^172720447 is an apocalyptic number.

172720447 is a deficient number, since it is larger than the sum of its proper divisors (1).

172720447 is an equidigital number, since it uses as much as digits as its factorization.

172720447 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21952, while the sum is 34.

The square root of 172720447 is about 13142.3151309044. The cubic root of 172720447 is about 556.9051718400.

The spelling of 172720447 in words is "one hundred seventy-two million, seven hundred twenty thousand, four hundred forty-seven".