172775621 has 2 divisors, whose sum is σ = 172775622. Its totient is φ = 172775620.

The previous prime is 172775593. The next prime is 172775623. The reversal of 172775621 is 126577271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 161010721 + 11764900 = 12689^2 + 3430^2 .

It is a cyclic number.

It is not a de Polignac number, because 172775621 - 2¹⁸ = 172513477 is a prime.

Together with 172775623, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172775623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86387810 + 86387811.

It is an arithmetic number, because the mean of its divisors is an integer number (86387811).

Almost surely, 2^172775621 is an apocalyptic number.

It is an amenable number.

172775621 is a deficient number, since it is larger than the sum of its proper divisors (1).

172775621 is an equidigital number, since it uses as much as digits as its factorization.

172775621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 41160, while the sum is 38.

The square root of 172775621 is about 13144.4140607332. The cubic root of 172775621 is about 556.9644649835.

The spelling of 172775621 in words is "one hundred seventy-two million, seven hundred seventy-five thousand, six hundred twenty-one".