21827718136721 has 16 divisors (see below), whose sum is σ = 25817146467840. Its totient is φ = 18056634388800.

The previous prime is 21827718136673. The next prime is 21827718136781. The reversal of 21827718136721 is 12763181772812.

It is not a de Polignac number, because 21827718136721 - 2¹⁰ = 21827718135697 is a prime.

It is a super-2 number, since 2×21827718136721² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21827718136781) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22390826 + ... + 23345331.

It is an arithmetic number, because the mean of its divisors is an integer number (1613571654240).

Almost surely, 2^{21827718136721} is an apocalyptic number.

It is an amenable number.

21827718136721 is a deficient number, since it is larger than the sum of its proper divisors (3989428331119).

21827718136721 is a wasteful number, since it uses less digits than its factorization.

21827718136721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45738544.

The product of its digits is 3161088, while the sum is 56.

The spelling of 21827718136721 in words is "twenty-one trillion, eight hundred twenty-seven billion, seven hundred eighteen million, one hundred thirty-six thousand, seven hundred twenty-one".