20543515521121 has 2 divisors, whose sum is σ = 20543515521122. Its totient is φ = 20543515521120.

The previous prime is 20543515521107. The next prime is 20543515521157. The reversal of 20543515521121 is 12112551534502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13937073431121 + 6606442090000 = 3733239^2 + 2570300^2 .

It is a cyclic number.

It is not a de Polignac number, because 20543515521121 - 2²³ = 20543507132513 is a prime.

It is not a weakly prime, because it can be changed into another prime (20543515521181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10271757760560 + 10271757760561.

It is an arithmetic number, because the mean of its divisors is an integer number (10271757760561).

Almost surely, 2^{20543515521121} is an apocalyptic number.

It is an amenable number.

20543515521121 is a deficient number, since it is larger than the sum of its proper divisors (1).

20543515521121 is an equidigital number, since it uses as much as digits as its factorization.

20543515521121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60000, while the sum is 37.

The spelling of 20543515521121 in words is "twenty trillion, five hundred forty-three billion, five hundred fifteen million, five hundred twenty-one thousand, one hundred twenty-one".