21587378665795 has 8 divisors (see below), whose sum is σ = 25926035808096. Its totient is φ = 17255781993216.

The previous prime is 21587378665781. The next prime is 21587378665799. The reversal of 21587378665795 is 59756687378512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21587378665795 - 2⁵ = 21587378665763 is a prime.

It is a super-2 number, since 2×21587378665795² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21587378665799) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1765110702 + ... + 1765122931.

It is an arithmetic number, because the mean of its divisors is an integer number (3240754476012).

Almost surely, 2^{21587378665795} is an apocalyptic number.

21587378665795 is a deficient number, since it is larger than the sum of its proper divisors (4338657142301).

21587378665795 is a wasteful number, since it uses less digits than its factorization.

21587378665795 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3530234861.

The product of its digits is 5334336000, while the sum is 79.

The spelling of 21587378665795 in words is "twenty-one trillion, five hundred eighty-seven billion, three hundred seventy-eight million, six hundred sixty-five thousand, seven hundred ninety-five".