20523909 has 32 divisors (see below), whose sum is σ = 32901120. Its totient is φ = 11132352.

The previous prime is 20523887. The next prime is 20523911. The reversal of 20523909 is 90932502.

It is not a de Polignac number, because 20523909 - 2⁸ = 20523653 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20523949) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 40552 + ... + 41054.

It is an arithmetic number, because the mean of its divisors is an integer number (1028160).

Almost surely, 2^20523909 is an apocalyptic number.

20523909 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20523909 is a deficient number, since it is larger than the sum of its proper divisors (12377211).

20523909 is a wasteful number, since it uses less digits than its factorization.

20523909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 609.

The product of its (nonzero) digits is 4860, while the sum is 30.

The square root of 20523909 is about 4530.3321070314. The cubic root of 20523909 is about 273.7915414116.

The spelling of 20523909 in words is "twenty million, five hundred twenty-three thousand, nine hundred nine".