21213123001 has 4 divisors (see below), whose sum is σ = 24243569152. Its totient is φ = 18182676852.

The previous prime is 21213122999. The next prime is 21213123011. The reversal of 21213123001 is 10032131212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21213123001 - 2¹ = 21213122999 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21213123011) 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, 1515223065 + ... + 1515223078.

It is an arithmetic number, because the mean of its divisors is an integer number (6060892288).

Almost surely, 2^21213123001 is an apocalyptic number.

It is an amenable number.

21213123001 is a deficient number, since it is larger than the sum of its proper divisors (3030446151).

21213123001 is an equidigital number, since it uses as much as digits as its factorization.

21213123001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3030446150.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21213123001 its reverse (10032131212), we get a palindrome (31245254213).

The spelling of 21213123001 in words is "twenty-one billion, two hundred thirteen million, one hundred twenty-three thousand, one".