20949193821221 has 4 divisors (see below), whose sum is σ = 20949254903052. Its totient is φ = 20949132739392.

The previous prime is 20949193821211. The next prime is 20949193821277. The reversal of 20949193821221 is 12212839194902.

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

It can be written as a sum of positive squares in 2 ways, for example, as 20538017908321 + 411175912900 = 4531889^2 + 641230^2 .

It is a cyclic number.

It is not a de Polignac number, because 20949193821221 - 2¹⁰ = 20949193820197 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20949193821211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30023540 + ... + 30713373.

It is an arithmetic number, because the mean of its divisors is an integer number (5237313725763).

Almost surely, 2^{20949193821221} is an apocalyptic number.

It is an amenable number.

20949193821221 is a deficient number, since it is larger than the sum of its proper divisors (61081831).

20949193821221 is an equidigital number, since it uses as much as digits as its factorization.

20949193821221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61081830.

The product of its (nonzero) digits is 1119744, while the sum is 53.

The spelling of 20949193821221 in words is "twenty trillion, nine hundred forty-nine billion, one hundred ninety-three million, eight hundred twenty-one thousand, two hundred twenty-one".