20172441875021 has 2 divisors, whose sum is σ = 20172441875022. Its totient is φ = 20172441875020.

The previous prime is 20172441875017. The next prime is 20172441875051. The reversal of 20172441875021 is 12057814427102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19279879864996 + 892562010025 = 4390886^2 + 944755^2 .

It is a cyclic number.

It is not a de Polignac number, because 20172441875021 - 2² = 20172441875017 is a prime.

It is a super-2 number, since 2×20172441875021² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20172441875051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10086220937510 + 10086220937511.

It is an arithmetic number, because the mean of its divisors is an integer number (10086220937511).

Almost surely, 2^{20172441875021} is an apocalyptic number.

It is an amenable number.

20172441875021 is a deficient number, since it is larger than the sum of its proper divisors (1).

20172441875021 is an equidigital number, since it uses as much as digits as its factorization.

20172441875021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 250880, while the sum is 44.

The spelling of 20172441875021 in words is "twenty trillion, one hundred seventy-two billion, four hundred forty-one million, eight hundred seventy-five thousand, twenty-one".