21213543326623 has 8 divisors (see below), whose sum is σ = 21408398805200. Its totient is φ = 21018692135808.

The previous prime is 21213543326581. The next prime is 21213543326639. The reversal of 21213543326623 is 32662334531212.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21213543326623 is a prime.

It is a super-2 number, since 2×21213543326623² (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 21213543326623.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213543326323) 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, 9329848 + ... + 11378626.

It is an arithmetic number, because the mean of its divisors is an integer number (2676049850650).

Almost surely, 2^{21213543326623} is an apocalyptic number.

21213543326623 is a deficient number, since it is larger than the sum of its proper divisors (194855478577).

21213543326623 is a wasteful number, since it uses less digits than its factorization.

21213543326623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2143881.

The product of its digits is 933120, while the sum is 43.

Adding to 21213543326623 its reverse (32662334531212), we get a palindrome (53875877857835).

The spelling of 21213543326623 in words is "twenty-one trillion, two hundred thirteen billion, five hundred forty-three million, three hundred twenty-six thousand, six hundred twenty-three".