21551544550551 has 8 divisors (see below), whose sum is σ = 28738967264640. Its totient is φ = 14365909101752.

The previous prime is 21551544550519. The next prime is 21551544550559. The reversal of 21551544550551 is 15505544515512.

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 21551544550551 - 2⁵ = 21551544550519 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21551544550551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21551544550559) 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, 446788185 + ... + 446836418.

It is an arithmetic number, because the mean of its divisors is an integer number (3592370908080).

Almost surely, 2^{21551544550551} is an apocalyptic number.

21551544550551 is a deficient number, since it is larger than the sum of its proper divisors (7187422714089).

21551544550551 is an equidigital number, since it uses as much as digits as its factorization.

21551544550551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 893632645.

The product of its (nonzero) digits is 2500000, while the sum is 48.

The spelling of 21551544550551 in words is "twenty-one trillion, five hundred fifty-one billion, five hundred forty-four million, five hundred fifty thousand, five hundred fifty-one".