21233231645 has 8 divisors (see below), whose sum is σ = 25503719640. Its totient is φ = 16970690880.

The previous prime is 21233231599. The next prime is 21233231653. The reversal of 21233231645 is 54613233212.

It can be written as a sum of positive squares in 4 ways, for example, as 1979449081 + 19253782564 = 44491^2 + 138758^2 .

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

It is not a de Polignac number, because 21233231645 - 2⁶ = 21233231581 is a prime.

It is a congruent number.

It is an unprimeable number.

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, 1980926 + ... + 1991615.

It is an arithmetic number, because the mean of its divisors is an integer number (3187964955).

Almost surely, 2^21233231645 is an apocalyptic number.

It is an amenable number.

21233231645 is a deficient number, since it is larger than the sum of its proper divisors (4270487995).

21233231645 is a wasteful number, since it uses less digits than its factorization.

21233231645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3973615.

The product of its digits is 25920, while the sum is 32.

Adding to 21233231645 its reverse (54613233212), we get a palindrome (75846464857).

The spelling of 21233231645 in words is "twenty-one billion, two hundred thirty-three million, two hundred thirty-one thousand, six hundred forty-five".