21661020001011 has 8 divisors (see below), whose sum is σ = 28881435295440. Its totient is φ = 14440642353632.

The previous prime is 21661020001003. The next prime is 21661020001043. The reversal of 21661020001011 is 11010002016612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21661020001011 - 2³ = 21661020001003 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21661020001211) 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, 8040696 + ... + 10391093.

It is an arithmetic number, because the mean of its divisors is an integer number (3610179411930).

Almost surely, 2^{21661020001011} is an apocalyptic number.

21661020001011 is a deficient number, since it is larger than the sum of its proper divisors (7220415294429).

21661020001011 is a wasteful number, since it uses less digits than its factorization.

21661020001011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18823525.

The product of its (nonzero) digits is 144, while the sum is 21.

Adding to 21661020001011 its reverse (11010002016612), we get a palindrome (32671022017623).

The spelling of 21661020001011 in words is "twenty-one trillion, six hundred sixty-one billion, twenty million, one thousand, eleven".