21145122013 has 4 divisors (see below), whose sum is σ = 22064475168. Its totient is φ = 20225768860.

The previous prime is 21145122001. The next prime is 21145122017. The reversal of 21145122013 is 31022154112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21145122013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21145122017) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 459676543 + ... + 459676588.

It is an arithmetic number, because the mean of its divisors is an integer number (5516118792).

Almost surely, 2^21145122013 is an apocalyptic number.

21145122013 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21145122013 is a deficient number, since it is larger than the sum of its proper divisors (919353155).

21145122013 is an equidigital number, since it uses as much as digits as its factorization.

21145122013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 919353154.

The product of its (nonzero) digits is 480, while the sum is 22.

Adding to 21145122013 its reverse (31022154112), we get a palindrome (52167276125).

The spelling of 21145122013 in words is "twenty-one billion, one hundred forty-five million, one hundred twenty-two thousand, thirteen".