21140343021 has 16 divisors (see below), whose sum is σ = 32228998784. Its totient is φ = 12074517504.

The previous prime is 21140342929. The next prime is 21140343023. The reversal of 21140343021 is 12034304112.

It is not a de Polignac number, because 21140343021 - 2⁷ = 21140342893 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21140343023) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 190660 + ... + 280413.

It is an arithmetic number, because the mean of its divisors is an integer number (2014312424).

Almost surely, 2^21140343021 is an apocalyptic number.

21140343021 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21140343021 is a deficient number, since it is larger than the sum of its proper divisors (11088655763).

21140343021 is a wasteful number, since it uses less digits than its factorization.

21140343021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 473220.

The product of its (nonzero) digits is 576, while the sum is 21.

Adding to 21140343021 its reverse (12034304112), we get a palindrome (33174647133).

The spelling of 21140343021 in words is "twenty-one billion, one hundred forty million, three hundred forty-three thousand, twenty-one".