21155152616065 has 16 divisors (see below), whose sum is σ = 27339069542400. Its totient is φ = 15622207641792.

The previous prime is 21155152616029. The next prime is 21155152616149. The reversal of 21155152616065 is 56061625155112.

It is a cyclic number.

It is not a de Polignac number, because 21155152616065 - 2¹⁵ = 21155152583297 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, 24779376 + ... + 25618894.

It is an arithmetic number, because the mean of its divisors is an integer number (1708691846400).

Almost surely, 2^{21155152616065} is an apocalyptic number.

It is an amenable number.

21155152616065 is a deficient number, since it is larger than the sum of its proper divisors (6183916926335).

21155152616065 is a wasteful number, since it uses less digits than its factorization.

21155152616065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1227216.

The product of its (nonzero) digits is 540000, while the sum is 46.

The spelling of 21155152616065 in words is "twenty-one trillion, one hundred fifty-five billion, one hundred fifty-two million, six hundred sixteen thousand, sixty-five".