172059721 has 2 divisors, whose sum is σ = 172059722. Its totient is φ = 172059720.

The previous prime is 172059707. The next prime is 172059733. The reversal of 172059721 is 127950271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 150798400 + 21261321 = 12280^2 + 4611^2 .

It is an emirp because it is prime and its reverse (127950271) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 172059721 - 2¹⁷ = 171928649 is a prime.

It is not a weakly prime, because it can be changed into another prime (172059221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86029860 + 86029861.

It is an arithmetic number, because the mean of its divisors is an integer number (86029861).

Almost surely, 2^172059721 is an apocalyptic number.

It is an amenable number.

172059721 is a deficient number, since it is larger than the sum of its proper divisors (1).

172059721 is an equidigital number, since it uses as much as digits as its factorization.

172059721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8820, while the sum is 34.

The square root of 172059721 is about 13117.1536927795. The cubic root of 172059721 is about 556.1941347590.

The spelling of 172059721 in words is "one hundred seventy-two million, fifty-nine thousand, seven hundred twenty-one".