20195009 has 2 divisors, whose sum is σ = 20195010. Its totient is φ = 20195008.

The previous prime is 20194973. The next prime is 20195011. The reversal of 20195009 is 90059102.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20070400 + 124609 = 4480^2 + 353^2 .

It is a cyclic number.

It is not a de Polignac number, because 20195009 - 2¹² = 20190913 is a prime.

Together with 20195011, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20195039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10097504 + 10097505.

It is an arithmetic number, because the mean of its divisors is an integer number (10097505).

Almost surely, 2^20195009 is an apocalyptic number.

It is an amenable number.

20195009 is a deficient number, since it is larger than the sum of its proper divisors (1).

20195009 is an equidigital number, since it uses as much as digits as its factorization.

20195009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 810, while the sum is 26.

The square root of 20195009 is about 4493.8857350849. The cubic root of 20195009 is about 272.3211361649.

The spelling of 20195009 in words is "twenty million, one hundred ninety-five thousand, nine".