221661536540660 has 24 divisors (see below), whose sum is σ = 465489832396680. Its totient is φ = 88664499252224.

The previous prime is 221661536540659. The next prime is 221661536540701. The reversal of 221661536540660 is 66045635166122.

It can be written as a sum of positive squares in 4 ways, for example, as 46590426215524 + 175071110325136 = 6825718^2 + 13231444^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9488576 + ... + 23094504.

It is an arithmetic number, because the mean of its divisors is an integer number (19395409683195).

Almost surely, 2^{221661536540660} is an apocalyptic number.

221661536540660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221661536540660 is an abundant number, since it is smaller than the sum of its proper divisors (243828295856020).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221661536540660 is a wasteful number, since it uses less digits than its factorization.

221661536540660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14420515 (or 14420513 counting only the distinct ones).

The product of its (nonzero) digits is 9331200, while the sum is 53.

The spelling of 221661536540660 in words is "two hundred twenty-one trillion, six hundred sixty-one billion, five hundred thirty-six million, five hundred forty thousand, six hundred sixty".