21123542020245 has 16 divisors (see below), whose sum is σ = 38625905408640. Its totient is φ = 9656476352064.

The previous prime is 21123542020169. The next prime is 21123542020261. The reversal of 21123542020245 is 54202024532112.

It is not a de Polignac number, because 21123542020245 - 2¹⁹ = 21123541495957 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 100588295230 + ... + 100588295439.

It is an arithmetic number, because the mean of its divisors is an integer number (2414119088040).

Almost surely, 2^{21123542020245} is an apocalyptic number.

It is an amenable number.

21123542020245 is a deficient number, since it is larger than the sum of its proper divisors (17502363388395).

21123542020245 is a wasteful number, since it uses less digits than its factorization.

21123542020245 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201176590684.

The product of its (nonzero) digits is 38400, while the sum is 33.

Adding to 21123542020245 its reverse (54202024532112), we get a palindrome (75325566552357).

The spelling of 21123542020245 in words is "twenty-one trillion, one hundred twenty-three billion, five hundred forty-two million, twenty thousand, two hundred forty-five".