21120656012511 has 8 divisors (see below), whose sum is σ = 30720954200064. Its totient is φ = 12800397583320.

The previous prime is 21120656012507. The next prime is 21120656012531. The reversal of 21120656012511 is 11521065602112.

It is a happy number.

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

It is not a de Polignac number, because 21120656012511 - 2² = 21120656012507 is a prime.

It is a super-2 number, since 2×21120656012511² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 640019879167 = 21120656012511 / (2 + 1 + 1 + 2 + 0 + 6 + 5 + 6 + 0 + 1 + 2 + 5 + 1 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21120656012531) 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, 320009939551 + ... + 320009939616.

It is an arithmetic number, because the mean of its divisors is an integer number (3840119275008).

Almost surely, 2^{21120656012511} is an apocalyptic number.

21120656012511 is a deficient number, since it is larger than the sum of its proper divisors (9600298187553).

21120656012511 is a wasteful number, since it uses less digits than its factorization.

21120656012511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 640019879181.

The product of its (nonzero) digits is 7200, while the sum is 33.

The spelling of 21120656012511 in words is "twenty-one trillion, one hundred twenty billion, six hundred fifty-six million, twelve thousand, five hundred eleven".