21166016310265 has 32 divisors (see below), whose sum is σ = 26929974960000. Its totient is φ = 15925253557248.

The previous prime is 21166016310251. The next prime is 21166016310287. The reversal of 21166016310265 is 56201361066112.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21166016310265 - 2¹⁹ = 21166015785977 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 285415411 + ... + 285489559.

It is an arithmetic number, because the mean of its divisors is an integer number (841561717500).

Almost surely, 2^{21166016310265} is an apocalyptic number.

It is an amenable number.

21166016310265 is a deficient number, since it is larger than the sum of its proper divisors (5763958649735).

21166016310265 is a wasteful number, since it uses less digits than its factorization.

21166016310265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95929.

The product of its (nonzero) digits is 77760, while the sum is 40.

Adding to 21166016310265 its reverse (56201361066112), we get a palindrome (77367377376377).

The spelling of 21166016310265 in words is "twenty-one trillion, one hundred sixty-six billion, sixteen million, three hundred ten thousand, two hundred sixty-five".