21312132403 has 4 divisors (see below), whose sum is σ = 21373551000. Its totient is φ = 21250713808.

The previous prime is 21312132389. The next prime is 21312132407. The reversal of 21312132403 is 30423121312.

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 21312132403 - 2²⁹ = 20775261491 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21312132407) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 30708778 + ... + 30709471.

It is an arithmetic number, because the mean of its divisors is an integer number (5343387750).

Almost surely, 2^21312132403 is an apocalyptic number.

21312132403 is a deficient number, since it is larger than the sum of its proper divisors (61418597).

21312132403 is an equidigital number, since it uses as much as digits as its factorization.

21312132403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61418596.

The product of its (nonzero) digits is 864, while the sum is 22.

Adding to 21312132403 its reverse (30423121312), we get a palindrome (51735253715).

The spelling of 21312132403 in words is "twenty-one billion, three hundred twelve million, one hundred thirty-two thousand, four hundred three".