21005767331233 has 4 divisors (see below), whose sum is σ = 21005975886660. Its totient is φ = 21005558775808.

The previous prime is 21005767331231. The next prime is 21005767331251. The reversal of 21005767331233 is 33213376750012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7478436416929 + 13527330914304 = 2734673^2 + 3677952^2 .

It is a cyclic number.

It is not a de Polignac number, because 21005767331233 - 2¹ = 21005767331231 is a prime.

It is a super-2 number, since 2×21005767331233² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21005767331233.

It is not an unprimeable number, because it can be changed into a prime (21005767331231) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104126560 + ... + 104328097.

It is an arithmetic number, because the mean of its divisors is an integer number (5251493971665).

Almost surely, 2^{21005767331233} is an apocalyptic number.

It is an amenable number.

21005767331233 is a deficient number, since it is larger than the sum of its proper divisors (208555427).

21005767331233 is a wasteful number, since it uses less digits than its factorization.

21005767331233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208555426.

The product of its (nonzero) digits is 476280, while the sum is 43.

The spelling of 21005767331233 in words is "twenty-one trillion, five billion, seven hundred sixty-seven million, three hundred thirty-one thousand, two hundred thirty-three".