21233000021 has 4 divisors (see below), whose sum is σ = 21234132000. Its totient is φ = 21231868044.

The previous prime is 21233000011. The next prime is 21233000059. The reversal of 21233000021 is 12000033212.

It is a happy number.

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 a de Polignac number, because none of the positive numbers 2^k-21233000021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21233000011) 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, 537371 + ... + 575528.

It is an arithmetic number, because the mean of its divisors is an integer number (5308533000).

Almost surely, 2^21233000021 is an apocalyptic number.

It is an amenable number.

21233000021 is a deficient number, since it is larger than the sum of its proper divisors (1131979).

21233000021 is a wasteful number, since it uses less digits than its factorization.

21233000021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1131978.

The product of its (nonzero) digits is 72, while the sum is 14.

Adding to 21233000021 its reverse (12000033212), we get a palindrome (33233033233).

The spelling of 21233000021 in words is "twenty-one billion, two hundred thirty-three million, twenty-one", and thus it is an aban number.