21210223541 has 8 divisors (see below), whose sum is σ = 23272756920. Its totient is φ = 19209258432.

The previous prime is 21210223537. The next prime is 21210223549. The reversal of 21210223541 is 14532201212.

It can be written as a sum of positive squares in 4 ways, for example, as 5380809316 + 15829414225 = 73354^2 + 125815^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21210223541 - 2² = 21210223537 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210223549) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15391346 + ... + 15392723.

It is an arithmetic number, because the mean of its divisors is an integer number (2909094615).

Almost surely, 2^21210223541 is an apocalyptic number.

It is an amenable number.

21210223541 is a deficient number, since it is larger than the sum of its proper divisors (2062533379).

21210223541 is a wasteful number, since it uses less digits than its factorization.

21210223541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30784135.

The product of its (nonzero) digits is 960, while the sum is 23.

Adding to 21210223541 its reverse (14532201212), we get a palindrome (35742424753).

The spelling of 21210223541 in words is "twenty-one billion, two hundred ten million, two hundred twenty-three thousand, five hundred forty-one".