21020321502143 has 4 divisors (see below), whose sum is σ = 21020331398688. Its totient is φ = 21020311605600.

The previous prime is 21020321502133. The next prime is 21020321502157. The reversal of 21020321502143 is 34120512302012.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21020321502143 - 2¹² = 21020321498047 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 (21020321502133) 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, 318071 + ... + 6491672.

It is an arithmetic number, because the mean of its divisors is an integer number (5255082849672).

Almost surely, 2^{21020321502143} is an apocalyptic number.

21020321502143 is a deficient number, since it is larger than the sum of its proper divisors (9896545).

21020321502143 is an equidigital number, since it uses as much as digits as its factorization.

21020321502143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9896544.

The product of its (nonzero) digits is 2880, while the sum is 26.

Adding to 21020321502143 its reverse (34120512302012), we get a palindrome (55140833804155).

The spelling of 21020321502143 in words is "twenty-one trillion, twenty billion, three hundred twenty-one million, five hundred two thousand, one hundred forty-three".