20249309 has 4 divisors (see below), whose sum is σ = 20261280. Its totient is φ = 20237340.

The previous prime is 20249291. The next prime is 20249311. The reversal of 20249309 is 90394202.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 20249309 - 2¹² = 20245213 is a prime.

It is a super-3 number, since 3×20249309³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20249399) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2927 + ... + 7004.

It is an arithmetic number, because the mean of its divisors is an integer number (5065320).

Almost surely, 2^20249309 is an apocalyptic number.

It is an amenable number.

20249309 is a deficient number, since it is larger than the sum of its proper divisors (11971).

20249309 is an equidigital number, since it uses as much as digits as its factorization.

20249309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11970.

The product of its (nonzero) digits is 3888, while the sum is 29.

The square root of 20249309 is about 4499.9232215672. The cubic root of 20249309 is about 272.5649885678.

The spelling of 20249309 in words is "twenty million, two hundred forty-nine thousand, three hundred nine".