21164231603 has 4 divisors (see below), whose sum is σ = 21164587368. Its totient is φ = 21163875840.

The previous prime is 21164231597. The next prime is 21164231623. The reversal of 21164231603 is 30613246112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21164231603 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21164231623) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 64601 + ... + 215642.

It is an arithmetic number, because the mean of its divisors is an integer number (5291146842).

Almost surely, 2^21164231603 is an apocalyptic number.

21164231603 is a deficient number, since it is larger than the sum of its proper divisors (355765).

21164231603 is an equidigital number, since it uses as much as digits as its factorization.

21164231603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 355764.

The product of its (nonzero) digits is 5184, while the sum is 29.

Adding to 21164231603 its reverse (30613246112), we get a palindrome (51777477715).

The spelling of 21164231603 in words is "twenty-one billion, one hundred sixty-four million, two hundred thirty-one thousand, six hundred three".