21661162581228 has 48 divisors (see below), whose sum is σ = 52574435528160. Its totient is φ = 6932892556800.

The previous prime is 21661162581211. The next prime is 21661162581239. The reversal of 21661162581228 is 82218526116612.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 171883753 + ... + 172009728.

It is an arithmetic number, because the mean of its divisors is an integer number (1095300740170).

Almost surely, 2^{21661162581228} is an apocalyptic number.

It is an amenable number.

21661162581228 is an abundant number, since it is smaller than the sum of its proper divisors (30913272946932).

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

21661162581228 is a wasteful number, since it uses less digits than its factorization.

21661162581228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 343893698 (or 343893696 counting only the distinct ones).

The product of its digits is 1105920, while the sum is 51.

The spelling of 21661162581228 in words is "twenty-one trillion, six hundred sixty-one billion, one hundred sixty-two million, five hundred eighty-one thousand, two hundred twenty-eight".