21626255065 has 4 divisors (see below), whose sum is σ = 25951506084. Its totient is φ = 17301004048.

The previous prime is 21626255059. The next prime is 21626255081. The reversal of 21626255065 is 56055262612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10517938249 + 11108316816 = 102557^2 + 105396^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21626255065 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2162625502 + ... + 2162625511.

It is an arithmetic number, because the mean of its divisors is an integer number (6487876521).

Almost surely, 2^21626255065 is an apocalyptic number.

It is an amenable number.

21626255065 is a deficient number, since it is larger than the sum of its proper divisors (4325251019).

21626255065 is an equidigital number, since it uses as much as digits as its factorization.

21626255065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4325251018.

The product of its (nonzero) digits is 216000, while the sum is 40.

The spelling of 21626255065 in words is "twenty-one billion, six hundred twenty-six million, two hundred fifty-five thousand, sixty-five".