21123300421545 has 48 divisors (see below), whose sum is σ = 39315731322240. Its totient is φ = 9656236402176.

The previous prime is 21123300421511. The next prime is 21123300421589. The reversal of 21123300421545 is 54512400332112.

It is not a de Polignac number, because 21123300421545 - 2²³ = 21123292032937 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 74139121 + ... + 74423489.

It is an arithmetic number, because the mean of its divisors is an integer number (819077735880).

Almost surely, 2^{21123300421545} is an apocalyptic number.

It is an amenable number.

21123300421545 is a deficient number, since it is larger than the sum of its proper divisors (18192430900695).

21123300421545 is a wasteful number, since it uses less digits than its factorization.

21123300421545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385454 (or 385447 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 33.

Adding to 21123300421545 its reverse (54512400332112), we get a palindrome (75635700753657).

The spelling of 21123300421545 in words is "twenty-one trillion, one hundred twenty-three billion, three hundred million, four hundred twenty-one thousand, five hundred forty-five".