21201011999966 has 16 divisors (see below), whose sum is σ = 32026551219600. Its totient is φ = 10525616601408.

The previous prime is 21201011999933. The next prime is 21201011999969. The reversal of 21201011999966 is 66999911010212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201011999969) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30069551 + ... + 30766538.

It is an arithmetic number, because the mean of its divisors is an integer number (2001659451225).

Almost surely, 2^{21201011999966} is an apocalyptic number.

21201011999966 is a deficient number, since it is larger than the sum of its proper divisors (10825539219634).

21201011999966 is a wasteful number, since it uses less digits than its factorization.

21201011999966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60837323.

The product of its (nonzero) digits is 944784, while the sum is 56.

The spelling of 21201011999966 in words is "twenty-one trillion, two hundred one billion, eleven million, nine hundred ninety-nine thousand, nine hundred sixty-six".