20126309 has 6 divisors (see below), whose sum is σ = 23412294. Its totient is φ = 17251080.

The previous prime is 20126297. The next prime is 20126321. The reversal of 20126309 is 90362102.

It is an interprime number because it is at equal distance from previous prime (20126297) and next prime (20126321).

It can be written as a sum of positive squares in only one way, i.e., 14822500 + 5303809 = 3850^2 + 2303^2 .

It is not a de Polignac number, because 20126309 - 2⁸ = 20126053 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 (20126329) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 205322 + ... + 205419.

It is an arithmetic number, because the mean of its divisors is an integer number (3902049).

Almost surely, 2^20126309 is an apocalyptic number.

It is an amenable number.

20126309 is a deficient number, since it is larger than the sum of its proper divisors (3285985).

20126309 is an equidigital number, since it uses as much as digits as its factorization.

20126309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410755 (or 410748 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 20126309 is about 4486.2355042953. The cubic root of 20126309 is about 272.0119885503.

The spelling of 20126309 in words is "twenty million, one hundred twenty-six thousand, three hundred nine".