20408923 has 4 divisors (see below), whose sum is σ = 20515968. Its totient is φ = 20301880.

The previous prime is 20408917. The next prime is 20408957. The reversal of 20408923 is 32980402.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20408923 - 2⁹ = 20408411 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20408891 and 20408900.

It is not an unprimeable number, because it can be changed into a prime (20405923) 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, 53236 + ... + 53617.

It is an arithmetic number, because the mean of its divisors is an integer number (5128992).

Almost surely, 2^20408923 is an apocalyptic number.

20408923 is a deficient number, since it is larger than the sum of its proper divisors (107045).

20408923 is a wasteful number, since it uses less digits than its factorization.

20408923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107044.

The product of its (nonzero) digits is 3456, while the sum is 28.

The square root of 20408923 is about 4517.6236009654. The cubic root of 20408923 is about 273.2792742916.

The spelling of 20408923 in words is "twenty million, four hundred eight thousand, nine hundred twenty-three".