2172400309 has 2 divisors, whose sum is σ = 2172400310. Its totient is φ = 2172400308.

The previous prime is 2172400297. The next prime is 2172400313. The reversal of 2172400309 is 9030042712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2141653284 + 30747025 = 46278^2 + 5545^2 .

It is a cyclic number.

It is not a de Polignac number, because 2172400309 - 2⁹ = 2172399797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2172400319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1086200154 + 1086200155.

It is an arithmetic number, because the mean of its divisors is an integer number (1086200155).

Almost surely, 2^2172400309 is an apocalyptic number.

It is an amenable number.

2172400309 is a deficient number, since it is larger than the sum of its proper divisors (1).

2172400309 is an equidigital number, since it uses as much as digits as its factorization.

2172400309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 2172400309 is about 46609.0153189273. The cubic root of 2172400309 is about 1295.1297672120.

The spelling of 2172400309 in words is "two billion, one hundred seventy-two million, four hundred thousand, three hundred nine".