21615612345111 has 16 divisors (see below), whose sum is σ = 29005418357600. Its totient is φ = 14318113799808.

The previous prime is 21615612345007. The next prime is 21615612345121. The reversal of 21615612345111 is 11154321651612.

It is not a de Polignac number, because 21615612345111 - 2²⁶ = 21615545236247 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21615612345111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21615612345121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12702705 + ... + 14303493.

It is an arithmetic number, because the mean of its divisors is an integer number (1812838647350).

Almost surely, 2^{21615612345111} is an apocalyptic number.

21615612345111 is a deficient number, since it is larger than the sum of its proper divisors (7389806012489).

21615612345111 is a wasteful number, since it uses less digits than its factorization.

21615612345111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1629618.

The product of its digits is 43200, while the sum is 39.

Adding to 21615612345111 its reverse (11154321651612), we get a palindrome (32769933996723).

The spelling of 21615612345111 in words is "twenty-one trillion, six hundred fifteen billion, six hundred twelve million, three hundred forty-five thousand, one hundred eleven".