21123023221 has 8 divisors (see below), whose sum is σ = 21347661888. Its totient is φ = 20899500000.

The previous prime is 21123023213. The next prime is 21123023231. The reversal of 21123023221 is 12232032112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21123023221 - 2³ = 21123023213 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 (21123023231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 240760 + ... + 316561.

It is an arithmetic number, because the mean of its divisors is an integer number (2668457736).

Almost surely, 2^21123023221 is an apocalyptic number.

It is an amenable number.

21123023221 is a deficient number, since it is larger than the sum of its proper divisors (224638667).

21123023221 is a wasteful number, since it uses less digits than its factorization.

21123023221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 557723.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21123023221 its reverse (12232032112), we get a palindrome (33355055333).

The spelling of 21123023221 in words is "twenty-one billion, one hundred twenty-three million, twenty-three thousand, two hundred twenty-one".