21420121420343 has 4 divisors (see below), whose sum is σ = 22547496231960. Its totient is φ = 20292746608728.

The previous prime is 21420121420337. The next prime is 21420121420349. The reversal of 21420121420343 is 34302412102412.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (21420121420337) and next prime (21420121420349).

It is a cyclic number.

It is not a de Polignac number, because 21420121420343 - 2³⁰ = 21419047678519 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 (21420121420349) 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, 563687405780 + ... + 563687405817.

It is an arithmetic number, because the mean of its divisors is an integer number (5636874057990).

Almost surely, 2^{21420121420343} is an apocalyptic number.

21420121420343 is a deficient number, since it is larger than the sum of its proper divisors (1127374811617).

21420121420343 is a wasteful number, since it uses less digits than its factorization.

21420121420343 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1127374811616.

The product of its (nonzero) digits is 9216, while the sum is 29.

Adding to 21420121420343 its reverse (34302412102412), we get a palindrome (55722533522755).

The spelling of 21420121420343 in words is "twenty-one trillion, four hundred twenty billion, one hundred twenty-one million, four hundred twenty thousand, three hundred forty-three".