20199409 has 2 divisors, whose sum is σ = 20199410. Its totient is φ = 20199408.

The previous prime is 20199397. The next prime is 20199427. The reversal of 20199409 is 90499102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19713600 + 485809 = 4440^2 + 697^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20199409 is a prime.

It is a super-2 number, since 2×20199409² = 816032247898562, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (20199209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10099704 + 10099705.

It is an arithmetic number, because the mean of its divisors is an integer number (10099705).

Almost surely, 2^20199409 is an apocalyptic number.

It is an amenable number.

20199409 is a deficient number, since it is larger than the sum of its proper divisors (1).

20199409 is an equidigital number, since it uses as much as digits as its factorization.

20199409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 20199409 is about 4494.3752624809. The cubic root of 20199409 is about 272.3409121071.

The spelling of 20199409 in words is "twenty million, one hundred ninety-nine thousand, four hundred nine".