21118468021 has 4 divisors (see below), whose sum is σ = 24135392032. Its totient is φ = 18101544012.

The previous prime is 21118468013. The next prime is 21118468031. The reversal of 21118468021 is 12086481112.

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 not a de Polignac number, because 21118468021 - 2³ = 21118468013 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 (21118468001) 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, 1508461995 + ... + 1508462008.

It is an arithmetic number, because the mean of its divisors is an integer number (6033848008).

Almost surely, 2^21118468021 is an apocalyptic number.

It is an amenable number.

21118468021 is a deficient number, since it is larger than the sum of its proper divisors (3016924011).

21118468021 is an equidigital number, since it uses as much as digits as its factorization.

21118468021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3016924010.

The product of its (nonzero) digits is 6144, while the sum is 34.

The spelling of 21118468021 in words is "twenty-one billion, one hundred eighteen million, four hundred sixty-eight thousand, twenty-one".