21655422261666 has 32 divisors (see below), whose sum is σ = 48164256504000. Its totient is φ = 7212309698880.

The previous prime is 21655422261617. The next prime is 21655422261689. The reversal of 21655422261666 is 66616222455612.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 171169191 + ... + 171295658.

It is an arithmetic number, because the mean of its divisors is an integer number (1505133015750).

Almost surely, 2^{21655422261666} is an apocalyptic number.

21655422261666 is an abundant number, since it is smaller than the sum of its proper divisors (26508834242334).

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

21655422261666 is a wasteful number, since it uses less digits than its factorization.

21655422261666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342466031 (or 342466025 counting only the distinct ones).

The product of its digits is 12441600, while the sum is 54.

The spelling of 21655422261666 in words is "twenty-one trillion, six hundred fifty-five billion, four hundred twenty-two million, two hundred sixty-one thousand, six hundred sixty-six".