21220265662643 has 4 divisors (see below), whose sum is σ = 21220290277920. Its totient is φ = 21220241047368.

The previous prime is 21220265662639. The next prime is 21220265662663. The reversal of 21220265662643 is 34626656202212.

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 21220265662643 - 2² = 21220265662639 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21220265662613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10965755 + ... + 12754932.

It is an arithmetic number, because the mean of its divisors is an integer number (5305072569480).

Almost surely, 2^{21220265662643} is an apocalyptic number.

21220265662643 is a deficient number, since it is larger than the sum of its proper divisors (24615277).

21220265662643 is an equidigital number, since it uses as much as digits as its factorization.

21220265662643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24615276.

The product of its (nonzero) digits is 2488320, while the sum is 47.

The spelling of 21220265662643 in words is "twenty-one trillion, two hundred twenty billion, two hundred sixty-five million, six hundred sixty-two thousand, six hundred forty-three".