21201133421 has 4 divisors (see below), whose sum is σ = 22831989852. Its totient is φ = 19570276992.

The previous prime is 21201133391. The next prime is 21201133433. The reversal of 21201133421 is 12433110212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7398408196 + 13802725225 = 86014^2 + 117485^2 .

It is a cyclic number.

It is not a de Polignac number, because 21201133421 - 2⁶ = 21201133357 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21201133393 and 21201133402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201133621) 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, 815428196 + ... + 815428221.

It is an arithmetic number, because the mean of its divisors is an integer number (5707997463).

Almost surely, 2^21201133421 is an apocalyptic number.

It is an amenable number.

21201133421 is a deficient number, since it is larger than the sum of its proper divisors (1630856431).

21201133421 is a wasteful number, since it uses less digits than its factorization.

21201133421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1630856430.

The product of its (nonzero) digits is 288, while the sum is 20.

Adding to 21201133421 its reverse (12433110212), we get a palindrome (33634243633).

The spelling of 21201133421 in words is "twenty-one billion, two hundred one million, one hundred thirty-three thousand, four hundred twenty-one".