20523351 has 4 divisors (see below), whose sum is σ = 27364472. Its totient is φ = 13682232.

The previous prime is 20523343. The next prime is 20523361. The reversal of 20523351 is 15332502.

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

It is not a de Polignac number, because 20523351 - 2³ = 20523343 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 (20523361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3420556 + ... + 3420561.

It is an arithmetic number, because the mean of its divisors is an integer number (6841118).

Almost surely, 2^20523351 is an apocalyptic number.

20523351 is a deficient number, since it is larger than the sum of its proper divisors (6841121).

20523351 is an equidigital number, since it uses as much as digits as its factorization.

20523351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6841120.

The product of its (nonzero) digits is 900, while the sum is 21.

The square root of 20523351 is about 4530.2705217238. The cubic root of 20523351 is about 273.7890601256.

Adding to 20523351 its reverse (15332502), we get a palindrome (35855853).

The spelling of 20523351 in words is "twenty million, five hundred twenty-three thousand, three hundred fifty-one".