21564242064155 has 32 divisors (see below), whose sum is σ = 29612918559744. Its totient is φ = 14767370591616.

The previous prime is 21564242064121. The next prime is 21564242064187. The reversal of 21564242064155 is 55146024246512.

It is a cyclic number.

It is not a de Polignac number, because 21564242064155 - 2⁸ = 21564242063899 is a prime.

It is a Duffinian number.

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, 85930994 + ... + 86181576.

It is an arithmetic number, because the mean of its divisors is an integer number (925403704992).

Almost surely, 2^{21564242064155} is an apocalyptic number.

21564242064155 is a deficient number, since it is larger than the sum of its proper divisors (8048676495589).

21564242064155 is a wasteful number, since it uses less digits than its factorization.

21564242064155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253835.

The product of its (nonzero) digits is 2304000, while the sum is 47.

The spelling of 21564242064155 in words is "twenty-one trillion, five hundred sixty-four billion, two hundred forty-two million, sixty-four thousand, one hundred fifty-five".