172978609 has 2 divisors, whose sum is σ = 172978610. Its totient is φ = 172978608.

The previous prime is 172978601. The next prime is 172978651. The reversal of 172978609 is 906879271.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 167780209 + 5198400 = 12953^2 + 2280^2 .

It is a cyclic number.

It is not a de Polignac number, because 172978609 - 2³ = 172978601 is a prime.

It is not a weakly prime, because it can be changed into another prime (172978601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86489304 + 86489305.

It is an arithmetic number, because the mean of its divisors is an integer number (86489305).

Almost surely, 2^172978609 is an apocalyptic number.

It is an amenable number.

172978609 is a deficient number, since it is larger than the sum of its proper divisors (1).

172978609 is an equidigital number, since it uses as much as digits as its factorization.

172978609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 381024, while the sum is 49.

The square root of 172978609 is about 13152.1332490209. The cubic root of 172978609 is about 557.1824989388.

The spelling of 172978609 in words is "one hundred seventy-two million, nine hundred seventy-eight thousand, six hundred nine".