21117026305 has 16 divisors (see below), whose sum is σ = 25941896640. Its totient is φ = 16493012928.

The previous prime is 21117026297. The next prime is 21117026321. The reversal of 21117026305 is 50362071112.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21117026305 - 2³ = 21117026297 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 460351 + ... + 504139.

It is an arithmetic number, because the mean of its divisors is an integer number (1621368540).

Almost surely, 2^21117026305 is an apocalyptic number.

It is an amenable number.

21117026305 is a deficient number, since it is larger than the sum of its proper divisors (4824870335).

21117026305 is a wasteful number, since it uses less digits than its factorization.

21117026305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46080.

The product of its (nonzero) digits is 2520, while the sum is 28.

Adding to 21117026305 its reverse (50362071112), we get a palindrome (71479097417).

The spelling of 21117026305 in words is "twenty-one billion, one hundred seventeen million, twenty-six thousand, three hundred five".