21240221041 has 16 divisors (see below), whose sum is σ = 23147948880. Its totient is φ = 19371939840.

The previous prime is 21240221029. The next prime is 21240221071. The reversal of 21240221041 is 14012204212.

It can be written as a sum of positive squares in 8 ways, for example, as 10816832016 + 10423389025 = 104004^2 + 102095^2 .

It is a cyclic number.

It is not a de Polignac number, because 21240221041 - 2¹⁵ = 21240188273 is a prime.

It is a super-2 number, since 2×21240221041² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21240221071) 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, 1790911 + ... + 1802731.

It is an arithmetic number, because the mean of its divisors is an integer number (1446746805).

Almost surely, 2^21240221041 is an apocalyptic number.

It is an amenable number.

21240221041 is a deficient number, since it is larger than the sum of its proper divisors (1907727839).

21240221041 is a wasteful number, since it uses less digits than its factorization.

21240221041 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13476.

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 21240221041 its reverse (14012204212), we get a palindrome (35252425253).

The spelling of 21240221041 in words is "twenty-one billion, two hundred forty million, two hundred twenty-one thousand, forty-one".