21261021455066 has 16 divisors (see below), whose sum is σ = 33570337970400. Its totient is φ = 10070918934768.

The previous prime is 21261021455059. The next prime is 21261021455081. The reversal of 21261021455066 is 66055412016212.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1812881 + ... + 6768203.

It is an arithmetic number, because the mean of its divisors is an integer number (2098146123150).

Almost surely, 2^{21261021455066} is an apocalyptic number.

21261021455066 is a deficient number, since it is larger than the sum of its proper divisors (12309316515334).

21261021455066 is a wasteful number, since it uses less digits than its factorization.

21261021455066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5068253.

The product of its (nonzero) digits is 172800, while the sum is 41.

The spelling of 21261021455066 in words is "twenty-one trillion, two hundred sixty-one billion, twenty-one million, four hundred fifty-five thousand, sixty-six".