21011254321523 has 8 divisors (see below), whose sum is σ = 22060194966480. Its totient is φ = 19983941318880.

The previous prime is 21011254321517. The next prime is 21011254321529. The reversal of 21011254321523 is 32512345211012.

It is an interprime number because it is at equal distance from previous prime (21011254321517) and next prime (21011254321529).

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 21011254321523 - 2¹⁸ = 21011254059379 is a prime.

It is a super-3 number, since 3×21011254321523³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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 21011254321523.

It is not an unprimeable number, because it can be changed into a prime (21011254321529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5406908588 + ... + 5406912473.

It is an arithmetic number, because the mean of its divisors is an integer number (2757524370810).

Almost surely, 2^{21011254321523} is an apocalyptic number.

21011254321523 is a deficient number, since it is larger than the sum of its proper divisors (1048940644957).

21011254321523 is a wasteful number, since it uses less digits than its factorization.

21011254321523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10813821157.

The product of its (nonzero) digits is 14400, while the sum is 32.

Adding to 21011254321523 its reverse (32512345211012), we get a palindrome (53523599532535).

The spelling of 21011254321523 in words is "twenty-one trillion, eleven billion, two hundred fifty-four million, three hundred twenty-one thousand, five hundred twenty-three".