20948309 has 4 divisors (see below), whose sum is σ = 21155820. Its totient is φ = 20740800.

The previous prime is 20948261. The next prime is 20948321. The reversal of 20948309 is 90384902.

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 9591409 + 11356900 = 3097^2 + 3370^2 .

It is a cyclic number.

It is not a de Polignac number, because 20948309 - 2²⁴ = 4171093 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 (20948339) 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, 103604 + ... + 103805.

It is an arithmetic number, because the mean of its divisors is an integer number (5288955).

Almost surely, 2^20948309 is an apocalyptic number.

It is an amenable number.

20948309 is a deficient number, since it is larger than the sum of its proper divisors (207511).

20948309 is a wasteful number, since it uses less digits than its factorization.

20948309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 207510.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 20948309 is about 4576.9322695447. The cubic root of 20948309 is about 275.6658641119.

The spelling of 20948309 in words is "twenty million, nine hundred forty-eight thousand, three hundred nine".