21111017405 has 8 divisors (see below), whose sum is σ = 25356195072. Its totient is φ = 16873497808.

The previous prime is 21111017359. The next prime is 21111017413. The reversal of 21111017405 is 50471011112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21111017405 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1908449 + ... + 1919478.

It is an arithmetic number, because the mean of its divisors is an integer number (3169524384).

Almost surely, 2^21111017405 is an apocalyptic number.

It is an amenable number.

21111017405 is a deficient number, since it is larger than the sum of its proper divisors (4245177667).

21111017405 is a wasteful number, since it uses less digits than its factorization.

21111017405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3829035.

The product of its (nonzero) digits is 280, while the sum is 23.

Adding to 21111017405 its reverse (50471011112), we get a palindrome (71582028517).

The spelling of 21111017405 in words is "twenty-one billion, one hundred eleven million, seventeen thousand, four hundred five".