20521021343 has 4 divisors (see below), whose sum is σ = 20768262648. Its totient is φ = 20273780040.

The previous prime is 20521021331. The next prime is 20521021373. The reversal of 20521021343 is 34312012502.

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 20521021343 - 2¹⁸ = 20520759199 is a prime.

It is a super-2 number, since 2×20521021343² (a number of 21 digits) 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 (20521021373) 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, 123620528 + ... + 123620693.

It is an arithmetic number, because the mean of its divisors is an integer number (5192065662).

Almost surely, 2^20521021343 is an apocalyptic number.

20521021343 is a deficient number, since it is larger than the sum of its proper divisors (247241305).

20521021343 is an equidigital number, since it uses as much as digits as its factorization.

20521021343 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 247241304.

The product of its (nonzero) digits is 1440, while the sum is 23.

Adding to 20521021343 its reverse (34312012502), we get a palindrome (54833033845).

The spelling of 20521021343 in words is "twenty billion, five hundred twenty-one million, twenty-one thousand, three hundred forty-three".