20471321 has 4 divisors (see below), whose sum is σ = 22046052. Its totient is φ = 18896592.

The previous prime is 20471291. The next prime is 20471327. The reversal of 20471321 is 12317402.

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 11833600 + 8637721 = 3440^2 + 2939^2 .

It is not a de Polignac number, because 20471321 - 2¹⁰ = 20470297 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20471293 and 20471302.

It is not an unprimeable number, because it can be changed into a prime (20471327) 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, 787346 + ... + 787371.

It is an arithmetic number, because the mean of its divisors is an integer number (5511513).

Almost surely, 2^20471321 is an apocalyptic number.

It is an amenable number.

20471321 is a deficient number, since it is larger than the sum of its proper divisors (1574731).

20471321 is a wasteful number, since it uses less digits than its factorization.

20471321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1574730.

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 20471321 is about 4524.5243948950. The cubic root of 20471321 is about 273.5574978793.

Adding to 20471321 its reverse (12317402), we get a palindrome (32788723).

The spelling of 20471321 in words is "twenty million, four hundred seventy-one thousand, three hundred twenty-one".