21312234403 has 4 divisors (see below), whose sum is σ = 21312687760. Its totient is φ = 21311781048.

The previous prime is 21312234397. The next prime is 21312234479. The reversal of 21312234403 is 30443221312.

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 21312234403 - 2¹³ = 21312226211 is a prime.

It is a super-2 number, since 2×21312234403² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21312235403) 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, 146775 + ... + 253312.

It is an arithmetic number, because the mean of its divisors is an integer number (5328171940).

Almost surely, 2^21312234403 is an apocalyptic number.

21312234403 is a deficient number, since it is larger than the sum of its proper divisors (453357).

21312234403 is an equidigital number, since it uses as much as digits as its factorization.

21312234403 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 453356.

The product of its (nonzero) digits is 3456, while the sum is 25.

Adding to 21312234403 its reverse (30443221312), we get a palindrome (51755455715).

The spelling of 21312234403 in words is "twenty-one billion, three hundred twelve million, two hundred thirty-four thousand, four hundred three".