21440202021 has 24 divisors (see below), whose sum is σ = 35819784000. Its totient is φ = 12103932096.

The previous prime is 21440201987. The next prime is 21440202029. The reversal of 21440202021 is 12020204412.

21440202021 is a `hidden beast` number, since 2 + 1 + 440 + 20 + 202 + 1 = 666.

It is not a de Polignac number, because 21440202021 - 2²³ = 21431813413 is a prime.

It is a super-3 number, since 3×21440202021³ (a number of 32 digits) contains 333 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21440201985 and 21440202003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440202029) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2044896 + ... + 2055353.

It is an arithmetic number, because the mean of its divisors is an integer number (1492491000).

Almost surely, 2^21440202021 is an apocalyptic number.

21440202021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21440202021 is a deficient number, since it is larger than the sum of its proper divisors (14379581979).

21440202021 is a wasteful number, since it uses less digits than its factorization.

21440202021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4100345 (or 4100342 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

Adding to 21440202021 its reverse (12020204412), we get a palindrome (33460406433).

The spelling of 21440202021 in words is "twenty-one billion, four hundred forty million, two hundred two thousand, twenty-one".