It is a Curzon number.
It is a self number, because there is not a number n which added to its sum of digits gives 21661465732410.
It is an unprimeable number.
Almost surely, 221661465732410 is an apocalyptic number.
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
21661465732410 is a wasteful number, since it uses less digits than its factorization.
21661465732410 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 56396956.
The spelling of 21661465732410 in words is "twenty-one trillion, six hundred sixty-one billion, four hundred sixty-five million, seven hundred thirty-two thousand, four hundred ten".