172725991 has 2 divisors, whose sum is σ = 172725992. Its totient is φ = 172725990.

The previous prime is 172725977. The next prime is 172725997. The reversal of 172725991 is 199527271.

It is a strong prime.

It is an emirp because it is prime and its reverse (199527271) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172725991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172725997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86362995 + 86362996.

It is an arithmetic number, because the mean of its divisors is an integer number (86362996).

Almost surely, 2^172725991 is an apocalyptic number.

172725991 is a deficient number, since it is larger than the sum of its proper divisors (1).

172725991 is an equidigital number, since it uses as much as digits as its factorization.

172725991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 79380, while the sum is 43.

The square root of 172725991 is about 13142.5260509538. The cubic root of 172725991 is about 556.9111303109.

The spelling of 172725991 in words is "one hundred seventy-two million, seven hundred twenty-five thousand, nine hundred ninety-one".