20725009 has 2 divisors, whose sum is σ = 20725010. Its totient is φ = 20725008.

The previous prime is 20725007. The next prime is 20725013. The reversal of 20725009 is 90052702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15563025 + 5161984 = 3945^2 + 2272^2 .

It is a cyclic number.

It is not a de Polignac number, because 20725009 - 2¹ = 20725007 is a prime.

Together with 20725007, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20725007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10362504 + 10362505.

It is an arithmetic number, because the mean of its divisors is an integer number (10362505).

Almost surely, 2^20725009 is an apocalyptic number.

It is an amenable number.

20725009 is a deficient number, since it is larger than the sum of its proper divisors (1).

20725009 is an equidigital number, since it uses as much as digits as its factorization.

20725009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 20725009 is about 4552.4728445099. The cubic root of 20725009 is about 274.6828696873.

The spelling of 20725009 in words is "twenty million, seven hundred twenty-five thousand, nine".