20309501 has 2 divisors, whose sum is σ = 20309502. Its totient is φ = 20309500.

The previous prime is 20309491. The next prime is 20309507. The reversal of 20309501 is 10590302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18062500 + 2247001 = 4250^2 + 1499^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20309501 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20309507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10154750 + 10154751.

It is an arithmetic number, because the mean of its divisors is an integer number (10154751).

Almost surely, 2^20309501 is an apocalyptic number.

It is an amenable number.

20309501 is a deficient number, since it is larger than the sum of its proper divisors (1).

20309501 is an equidigital number, since it uses as much as digits as its factorization.

20309501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 270, while the sum is 20.

The square root of 20309501 is about 4506.6063728708. The cubic root of 20309501 is about 272.8347920541.

Adding to 20309501 its reverse (10590302), we get a palindrome (30899803).

The spelling of 20309501 in words is "twenty million, three hundred nine thousand, five hundred one".