172642661 has 2 divisors, whose sum is σ = 172642662. Its totient is φ = 172642660.

The previous prime is 172642619. The next prime is 172642693. The reversal of 172642661 is 166246271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 151757761 + 20884900 = 12319^2 + 4570^2 .

It is an emirp because it is prime and its reverse (166246271) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172642661 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172642601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86321330 + 86321331.

It is an arithmetic number, because the mean of its divisors is an integer number (86321331).

Almost surely, 2^172642661 is an apocalyptic number.

It is an amenable number.

172642661 is a deficient number, since it is larger than the sum of its proper divisors (1).

172642661 is an equidigital number, since it uses as much as digits as its factorization.

172642661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 24192, while the sum is 35.

The square root of 172642661 is about 13139.3554255907. The cubic root of 172642661 is about 556.8215570911.

The spelling of 172642661 in words is "one hundred seventy-two million, six hundred forty-two thousand, six hundred sixty-one".