20521343 has 4 divisors (see below), whose sum is σ = 20810448. Its totient is φ = 20232240.

The previous prime is 20521339. The next prime is 20521373. The reversal of 20521343 is 34312502.

It is a happy number.

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 20521343 - 2² = 20521339 is a prime.

It is a super-2 number, since 2×20521343² = 842251037047298, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20521373) 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, 144446 + ... + 144587.

It is an arithmetic number, because the mean of its divisors is an integer number (5202612).

Almost surely, 2^20521343 is an apocalyptic number.

20521343 is a deficient number, since it is larger than the sum of its proper divisors (289105).

20521343 is an equidigital number, since it uses as much as digits as its factorization.

20521343 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289104.

The product of its (nonzero) digits is 720, while the sum is 20.

The square root of 20521343 is about 4530.0488959834. The cubic root of 20521343 is about 273.7801306813.

Adding to 20521343 its reverse (34312502), we get a palindrome (54833845).

The spelling of 20521343 in words is "twenty million, five hundred twenty-one thousand, three hundred forty-three".