21597310123 has 4 divisors (see below), whose sum is σ = 21612749200. Its totient is φ = 21581871048.

The previous prime is 21597310121. The next prime is 21597310159. The reversal of 21597310123 is 32101379512.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21597310123 - 2¹ = 21597310121 is a prime.

It is a super-3 number, since 3×21597310123³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21597310121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7717440 + ... + 7720237.

It is an arithmetic number, because the mean of its divisors is an integer number (5403187300).

Almost surely, 2^21597310123 is an apocalyptic number.

21597310123 is a deficient number, since it is larger than the sum of its proper divisors (15439077).

21597310123 is a wasteful number, since it uses less digits than its factorization.

21597310123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15439076.

The product of its (nonzero) digits is 11340, while the sum is 34.

Adding to 21597310123 its reverse (32101379512), we get a palindrome (53698689635).

The spelling of 21597310123 in words is "twenty-one billion, five hundred ninety-seven million, three hundred ten thousand, one hundred twenty-three".