20945222199721 has 8 divisors (see below), whose sum is σ = 21168006895944. Its totient is φ = 20722739587200.

The previous prime is 20945222199709. The next prime is 20945222199761. The reversal of 20945222199721 is 12799122254902.

It can be written as a sum of positive squares in 4 ways, for example, as 17364180691225 + 3581041508496 = 4167035^2 + 1892364^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20945222199721 - 2²⁵ = 20945188645289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20945222199761) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75381516 + ... + 75658861.

It is an arithmetic number, because the mean of its divisors is an integer number (2646000861993).

Almost surely, 2^{20945222199721} is an apocalyptic number.

It is an amenable number.

20945222199721 is a deficient number, since it is larger than the sum of its proper divisors (222784696223).

20945222199721 is a wasteful number, since it uses less digits than its factorization.

20945222199721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151041851.

The product of its (nonzero) digits is 3265920, while the sum is 55.

The spelling of 20945222199721 in words is "twenty trillion, nine hundred forty-five billion, two hundred twenty-two million, one hundred ninety-nine thousand, seven hundred twenty-one".