21043510221 has 16 divisors (see below), whose sum is σ = 29370317184. Its totient is φ = 13376704704.

The previous prime is 21043510219. The next prime is 21043510289. The reversal of 21043510221 is 12201534012.

It is not a de Polignac number, because 21043510221 - 2¹ = 21043510219 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21043510121) 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, 459166 + ... + 502911.

It is an arithmetic number, because the mean of its divisors is an integer number (1835644824).

Almost surely, 2^21043510221 is an apocalyptic number.

It is an amenable number.

21043510221 is a deficient number, since it is larger than the sum of its proper divisors (8326806963).

21043510221 is a wasteful number, since it uses less digits than its factorization.

21043510221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 962420.

The product of its (nonzero) digits is 480, while the sum is 21.

The spelling of 21043510221 in words is "twenty-one billion, forty-three million, five hundred ten thousand, two hundred twenty-one".