20353709 has 4 divisors (see below), whose sum is σ = 21551004. Its totient is φ = 19156416.

The previous prime is 20353703. The next prime is 20353721. The reversal of 20353709 is 90735302.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18966025 + 1387684 = 4355^2 + 1178^2 .

It is not a de Polignac number, because 20353709 - 2¹² = 20349613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20353703) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 598622 + ... + 598655.

It is an arithmetic number, because the mean of its divisors is an integer number (5387751).

Almost surely, 2^20353709 is an apocalyptic number.

It is an amenable number.

20353709 is a deficient number, since it is larger than the sum of its proper divisors (1197295).

20353709 is a wasteful number, since it uses less digits than its factorization.

20353709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1197294.

The product of its (nonzero) digits is 5670, while the sum is 29.

The square root of 20353709 is about 4511.5085060321. The cubic root of 20353709 is about 273.0326098076.

The spelling of 20353709 in words is "twenty million, three hundred fifty-three thousand, seven hundred nine".