20924009 has 4 divisors (see below), whose sum is σ = 20995716. Its totient is φ = 20852304.

The previous prime is 20924003. The next prime is 20924011. The reversal of 20924009 is 90042902.

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 15960025 + 4963984 = 3995^2 + 2228^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20924009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20924003) 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, 35414 + ... + 35999.

It is an arithmetic number, because the mean of its divisors is an integer number (5248929).

Almost surely, 2^20924009 is an apocalyptic number.

It is an amenable number.

20924009 is a deficient number, since it is larger than the sum of its proper divisors (71707).

20924009 is an equidigital number, since it uses as much as digits as its factorization.

20924009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71706.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 20924009 is about 4574.2768827433. The cubic root of 20924009 is about 275.5592322382.

The spelling of 20924009 in words is "twenty million, nine hundred twenty-four thousand, nine".