20523487 has 4 divisors (see below), whose sum is σ = 20555856. Its totient is φ = 20491120.

The previous prime is 20523479. The next prime is 20523491. The reversal of 20523487 is 78432502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78432502 = 2 ⋅39216251.

It is a cyclic number.

It is not a de Polignac number, because 20523487 - 2³ = 20523479 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20523407) 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, 15214 + ... + 16507.

It is an arithmetic number, because the mean of its divisors is an integer number (5138964).

Almost surely, 2^20523487 is an apocalyptic number.

20523487 is a deficient number, since it is larger than the sum of its proper divisors (32369).

20523487 is an equidigital number, since it uses as much as digits as its factorization.

20523487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32368.

The product of its (nonzero) digits is 13440, while the sum is 31.

The square root of 20523487 is about 4530.2855318401. The cubic root of 20523487 is about 273.7896648877.

Adding to 20523487 its reverse (78432502), we get a palindrome (98955989).

The spelling of 20523487 in words is "twenty million, five hundred twenty-three thousand, four hundred eighty-seven".