21180650065 has 16 divisors (see below), whose sum is σ = 26085338496. Its totient is φ = 16504566400.

The previous prime is 21180650041. The next prime is 21180650089. The reversal of 21180650065 is 56005608112.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21180650041) and next prime (21180650089).

It is not a de Polignac number, because 21180650065 - 2¹⁹ = 21180125777 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 21180650065.

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, 329956 + ... + 388885.

It is an arithmetic number, because the mean of its divisors is an integer number (1630333656).

Almost surely, 2^21180650065 is an apocalyptic number.

It is an amenable number.

21180650065 is a deficient number, since it is larger than the sum of its proper divisors (4904688431).

21180650065 is an equidigital number, since it uses as much as digits as its factorization.

21180650065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 719000.

The product of its (nonzero) digits is 14400, while the sum is 34.

The spelling of 21180650065 in words is "twenty-one billion, one hundred eighty million, six hundred fifty thousand, sixty-five".