21231554353493 has 16 divisors (see below), whose sum is σ = 23298928598400. Its totient is φ = 19187225956800.

The previous prime is 21231554353417. The next prime is 21231554353571. The reversal of 21231554353493 is 39435345513212.

It is not a de Polignac number, because 21231554353493 - 2⁸ = 21231554353237 is a prime.

It is a super-2 number, since 2×21231554353493² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21231554355493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1896518 + ... + 6786743.

It is an arithmetic number, because the mean of its divisors is an integer number (1456183037400).

Almost surely, 2^{21231554353493} is an apocalyptic number.

It is an amenable number.

21231554353493 is a deficient number, since it is larger than the sum of its proper divisors (2067374244907).

21231554353493 is a wasteful number, since it uses less digits than its factorization.

21231554353493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8684588.

The product of its digits is 5832000, while the sum is 50.

The spelling of 21231554353493 in words is "twenty-one trillion, two hundred thirty-one billion, five hundred fifty-four million, three hundred fifty-three thousand, four hundred ninety-three".