21231554353531 has 8 divisors (see below), whose sum is σ = 21263388300000. Its totient is φ = 21199737947520.

The previous prime is 21231554353417. The next prime is 21231554353571. The reversal of 21231554353531 is 13535345513212.

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 21231554353531 - 2²¹ = 21231552256379 is a prime.

It is a super-2 number, since 2×21231554353531² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21231554353571) 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, 1961431 + ... + 6805168.

It is an arithmetic number, because the mean of its divisors is an integer number (2657923537500).

Almost surely, 2^{21231554353531} is an apocalyptic number.

21231554353531 is a deficient number, since it is larger than the sum of its proper divisors (31833946469).

21231554353531 is an equidigital number, since it uses as much as digits as its factorization.

21231554353531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8770229.

The product of its digits is 810000, while the sum is 43.

Adding to 21231554353531 its reverse (13535345513212), we get a palindrome (34766899866743).

The spelling of 21231554353531 in words is "twenty-one trillion, two hundred thirty-one billion, five hundred fifty-four million, three hundred fifty-three thousand, five hundred thirty-one".