21706117165165 has 32 divisors (see below), whose sum is σ = 26718287904000. Its totient is φ = 16923190422528.

The previous prime is 21706117165147. The next prime is 21706117165169. The reversal of 21706117165165 is 56156171160712.

It is a cyclic number.

It is not a de Polignac number, because 21706117165165 - 2⁴¹ = 19507093909613 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21706117165169) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19798501 + ... + 20866069.

It is an arithmetic number, because the mean of its divisors is an integer number (834946497000).

Almost surely, 2^{21706117165165} is an apocalyptic number.

It is an amenable number.

21706117165165 is a deficient number, since it is larger than the sum of its proper divisors (5012170738835).

21706117165165 is a wasteful number, since it uses less digits than its factorization.

21706117165165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1068229.

The product of its (nonzero) digits is 529200, while the sum is 49.

The spelling of 21706117165165 in words is "twenty-one trillion, seven hundred six billion, one hundred seventeen million, one hundred sixty-five thousand, one hundred sixty-five".