21311017405 has 8 divisors (see below), whose sum is σ = 26919180000. Its totient is φ = 16151507856.

The previous prime is 21311017373. The next prime is 21311017489. The reversal of 21311017405 is 50471011312.

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

It is a cyclic number.

It is not a de Polignac number, because 21311017405 - 2⁵ = 21311017373 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21311017405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 112163155 + ... + 112163344.

It is an arithmetic number, because the mean of its divisors is an integer number (3364897500).

Almost surely, 2^21311017405 is an apocalyptic number.

It is an amenable number.

21311017405 is a deficient number, since it is larger than the sum of its proper divisors (5608162595).

21311017405 is a wasteful number, since it uses less digits than its factorization.

21311017405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224326523.

The product of its (nonzero) digits is 840, while the sum is 25.

Adding to 21311017405 its reverse (50471011312), we get a palindrome (71782028717).

The spelling of 21311017405 in words is "twenty-one billion, three hundred eleven million, seventeen thousand, four hundred five".