21140400021 has 48 divisors (see below), whose sum is σ = 31834856256. Its totient is φ = 12403784448.

The previous prime is 21140400011. The next prime is 21140400037. The reversal of 21140400021 is 12000404112.

It is not a de Polignac number, because 21140400021 - 2¹⁵ = 21140367253 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21140400011) 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 47 ways as a sum of consecutive naturals, for example, 7157481 + ... + 7160433.

It is an arithmetic number, because the mean of its divisors is an integer number (663226172).

Almost surely, 2^21140400021 is an apocalyptic number.

It is an amenable number.

21140400021 is a deficient number, since it is larger than the sum of its proper divisors (10694456235).

21140400021 is a wasteful number, since it uses less digits than its factorization.

21140400021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3362 (or 3339 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21140400021 its reverse (12000404112), we get a palindrome (33140804133).

The spelling of 21140400021 in words is "twenty-one billion, one hundred forty million, four hundred thousand, twenty-one".