18276065721 has 27 divisors (see below), whose sum is σ = 27429140271. Its totient is φ = 12176743608.

The previous prime is 18276065711. The next prime is 18276065749. The reversal of 18276065721 is 12756067281.

The square root of 18276065721 is 135189.

It is a perfect power (a square), and thus also a powerful number.

18276065721 is a `hidden beast` number, since 1 + 8 + 2 + 76 + 0 + 6 + 572 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 9749390121 + 8526675600 = 98739^2 + 92340^2 .

It is a tau number, because it is divible by the number of its divisors (27).

It is not a de Polignac number, because 18276065721 - 2¹⁵ = 18276032953 is a prime.

It is a super-2 number, since 2×18276065721² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (18276065701) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 10949475 + ... + 10951143.

Almost surely, 2^18276065721 is an apocalyptic number.

18276065721 is the 135189-th square number.

18276065721 is the 67595-th centered octagonal number.

It is an amenable number.

18276065721 is a deficient number, since it is larger than the sum of its proper divisors (9153074550).

18276065721 is an frugal number, since it uses more digits than its factorization.

18276065721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3362 (or 1672 counting only the distinct ones).

The product of its (nonzero) digits is 282240, while the sum is 45.

The spelling of 18276065721 in words is "eighteen billion, two hundred seventy-six million, sixty-five thousand, seven hundred twenty-one".