21253365632165 has 16 divisors (see below), whose sum is σ = 25568213424768. Its totient is φ = 16959929228736.

The previous prime is 21253365632131. The next prime is 21253365632167. The reversal of 21253365632165 is 56123656335212.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21253365632165 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21253365632167) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7350104 + ... + 9825006.

It is an arithmetic number, because the mean of its divisors is an integer number (1598013339048).

Almost surely, 2^{21253365632165} is an apocalyptic number.

It is an amenable number.

21253365632165 is a deficient number, since it is larger than the sum of its proper divisors (4314847792603).

21253365632165 is a wasteful number, since it uses less digits than its factorization.

21253365632165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2479228.

The product of its digits is 5832000, while the sum is 50.

The spelling of 21253365632165 in words is "twenty-one trillion, two hundred fifty-three billion, three hundred sixty-five million, six hundred thirty-two thousand, one hundred sixty-five".